Assuming that the Lazica under Persian protection isn't as oppressive as normally IRL, and Persians doesn't react when Justinian had been advancing very far against Ostrogoths, how far Justinian's campaigns would go?
MY PERSONAL OPINION...
Gothic War would end very early in Ostrogoths' front (and more territories got from it because it would probably include Pannonian areas), then Gothic War would go even further into crushing Visigoths (OH YEAH!) later on. It's probable that Mauritania would been annexed back into Romans to help creating more space for a southern front against Visigoths and very likely would attack Chlothar's domains in Provence region so to help create a land front via northeast areas of Visigothic Kingdom. Then for surely Franks would try to intervene in Visigoths who will cause a big trouble (only if Plague of Justinian happens) in the campaigns. Since Plague of Justinian doesn't exist in this time the problem would be not as major as PoJ happens. Then after all of that (Visigoths crushed, Franks weakened), Suevi Kingdom would be conquered easily and Basques are subdued then Gaul campaign will happen. Gaul campaign i'm expecting it'll be a massive campaign though in the end (about late 550's) all of the enemies (FRANKS) will be defeated. Byzantine Empire is pretty much weakened at this point since they waste many resources during this campaign. (with PoJ, it wouldn't reach Gaul at this point. Visigoths would be conquered but not the Franks. with Sassanid Empire attack it would have been the same.) Lombards would raid Pannonia many times during the war but i'll expect they will be always subdued, until they reach Feoderati status later on in the campaign. A slight extension of the Gaul Campaign, Liberius may help Justinian to get Brittany into the Byzantine Empire. Oh and at the time in the earliest times of Gaul Campaign there is also a campaign against Gepids and regain Dacia as a province. Byzantines ally & feoderatize Lombards and attack the western areas of Gepid territory. Byzantines it self would attack Gepids in eastern areas (same areas Trajan used to occupy). It was successful and Dacia is directly annexed by Byzantines though won't last long as Avars would occupy it later. After the Gaul Campaign (after Brittany is conquered), some tried to pressure Justinian to do further campaigns, and to appease them Justinian targets Saxony (and Frisia) for conquest while feoderatize remaining Germanic kingdoms in Inland Europe (Thuringia and Bavaria). Successful, Justinian declares the end of these campaigns and began to focus on rebuilding of the Byzantine Empire who is highly weakened by wars right now, appearing in somewhat closer in anarchy. There are plans to start conquest of Britain but due to the weakening of the empire (the extent is probably similar to OTL Byzantine Empire but with different causes instead) it seems impossible right now. Finally, sometime after (probably months) Justinian dies and Justin, son of Vigilantia takes the throne. He would try to invade Britain some years after he takes the throne but it fails horribly, also wars against Avars go badly too, causing him to lose his mind. Persians finally break it's very long truce and declared war against Byzantines with stronger than normally it do, and conquered Germanic peoples like Franks, Saxons, Frisians, etc. rebel in Gaul, also Plague of Justin II happens also and all of these caused Justin II to commit suicide because of... well, EXTREME INSANITY. I'll end my events now.
With a major POD that Sassanids didn't break truce and Plague of Justinian doesn't occur, Justinian would actually realize his ambitions to restore Roman Empire... for least. And such Justinian would have been seen as restorer of Roman Empire in this ATL to the further extent.
That's my opinion for now. Probably my view would be fully wrong, so i would like to see corrections from it, from your answers in this question. Anyway, thanks!
MY PERSONAL OPINION...
Gothic War would end very early in Ostrogoths' front (and more territories got from it because it would probably include Pannonian areas), then Gothic War would go even further into crushing Visigoths (OH YEAH!) later on. It's probable that Mauritania would been annexed back into Romans to help creating more space for a southern front against Visigoths and very likely would attack Chlothar's domains in Provence region so to help create a land front via northeast areas of Visigothic Kingdom. Then for surely Franks would try to intervene in Visigoths who will cause a big trouble (only if Plague of Justinian happens) in the campaigns. Since Plague of Justinian doesn't exist in this time the problem would be not as major as PoJ happens. Then after all of that (Visigoths crushed, Franks weakened), Suevi Kingdom would be conquered easily and Basques are subdued then Gaul campaign will happen. Gaul campaign i'm expecting it'll be a massive campaign though in the end (about late 550's) all of the enemies (FRANKS) will be defeated. Byzantine Empire is pretty much weakened at this point since they waste many resources during this campaign. (with PoJ, it wouldn't reach Gaul at this point. Visigoths would be conquered but not the Franks. with Sassanid Empire attack it would have been the same.) Lombards would raid Pannonia many times during the war but i'll expect they will be always subdued, until they reach Feoderati status later on in the campaign. A slight extension of the Gaul Campaign, Liberius may help Justinian to get Brittany into the Byzantine Empire. Oh and at the time in the earliest times of Gaul Campaign there is also a campaign against Gepids and regain Dacia as a province. Byzantines ally & feoderatize Lombards and attack the western areas of Gepid territory. Byzantines it self would attack Gepids in eastern areas (same areas Trajan used to occupy). It was successful and Dacia is directly annexed by Byzantines though won't last long as Avars would occupy it later. After the Gaul Campaign (after Brittany is conquered), some tried to pressure Justinian to do further campaigns, and to appease them Justinian targets Saxony (and Frisia) for conquest while feoderatize remaining Germanic kingdoms in Inland Europe (Thuringia and Bavaria). Successful, Justinian declares the end of these campaigns and began to focus on rebuilding of the Byzantine Empire who is highly weakened by wars right now, appearing in somewhat closer in anarchy. There are plans to start conquest of Britain but due to the weakening of the empire (the extent is probably similar to OTL Byzantine Empire but with different causes instead) it seems impossible right now. Finally, sometime after (probably months) Justinian dies and Justin, son of Vigilantia takes the throne. He would try to invade Britain some years after he takes the throne but it fails horribly, also wars against Avars go badly too, causing him to lose his mind. Persians finally break it's very long truce and declared war against Byzantines with stronger than normally it do, and conquered Germanic peoples like Franks, Saxons, Frisians, etc. rebel in Gaul, also Plague of Justin II happens also and all of these caused Justin II to commit suicide because of... well, EXTREME INSANITY. I'll end my events now.
With a major POD that Sassanids didn't break truce and Plague of Justinian doesn't occur, Justinian would actually realize his ambitions to restore Roman Empire... for least. And such Justinian would have been seen as restorer of Roman Empire in this ATL to the further extent.
That's my opinion for now. Probably my view would be fully wrong, so i would like to see corrections from it, from your answers in this question. Anyway, thanks!