WI Battle of Pliska never happens?

While Nicephorus I and his army were busy plundering the Bulgarian capital, Krum mobilized his people (including the women) to set traps and ambushes in the mountain passes. Initially Nicephorus intended to march through Moesia and reach Serdica before returning to Constantinople, but the news of these preparations for a battle changed his decision and he chose the shortest way back to his capital. On 25 July his army entered the Vărbitsa Pass but the road was barred with thick wooden walls and Krum's detachments watched from the heights around. The emperor became panicked by the situation and repeatedly told his companions that they were trapped and imminent death awaited them.
WI Nikephorus hadnt chose the shortest path and avoided the narrow pass that lead to his doom? He could draw Krum in Moesia and defeat him there in open field... How is History altered if Battle of Pliska never happens? Any thoughts?

The big question is, can Nicephorus, who comes from a civil service background, and who is not necessarily a brilliant military leader, defeat Krum, who is not only an adherent to the "hit and run" tactic (and thus tends to avoid pitched battles unless there is a good reason for him to do so - see the fate of Michael Rhangabe and the involvement of Leo the Armenian, future Leo V), but who is also one of the most brilliant military leaders medieval Bulgaria has ever produced? Somehow, I think the result would be less one-sided, but Nicephorus may still suffer defeat, unless he somehow manages to get lucky, has some intelligent generals giving him advice he will listen to, AND can force a pitched battle.

If these things do happen, then perhaps the rise of the Bulgarian Tsardom can be more or less prevented in its infancy. I would imagine that victorious Nicephorus may end up trying to make Bulgaria a Roman province, with all sorts of interesting butterflies down the line. Not sure if it will make the Empire stronger, as the Arabs are still an unknown factor (and consequently, additional expense required to pacify Bulgaria may mean there are less forces available to deal with the Arab incursions), and it is anyone's guess as to how it will affect the reconquest of Italy, still many Emperor's dream project.

Of course, there is also an opposite view. If Nicephorus manages to not only defeat Bulgaria, but also conquer and pacify it, a major thorn in the Empire's side could be removed for the foreseeable future (although how long it will last is anyone's guess). This may actually allow the Empire to field larger and better equipped and financed forces against the Arabs in the East, and against the Lombards in Italy. Especially if it does not have to keep on fighting off the Bulgars for the next two centuries. But considering that the Bulgars still reasserted their independence even after almost two centuries of Imperial rule, I doubt that the separatist ambition will go away. In fact, it may always linger there, to be exploited at the most inopportune moment.

Arabs werent really a threat by that time since there was an internal struggle for power between the successors of Caliph Harun al Rashid from 809 and on... So if Nicephorus had wiped out Bulgarians he would be free to expand the Empire to the West... By incorporating Venice back to Byzantine Empire (Venice was de jure Byzantine territory BUT de facto independent) attacking Lombards... Papal states would have surrendered easily to a strong Emperor...
One thing i cant calculate is Charlemagne's reaction... Maybe Nicephorus could "bribe" him by recognising his title as Western Roman Emperor in exchange for his neutrality...