Very much it, although i think an surviving Kiliç Arslan probably would have the experience on his side against John, i'm not safe to say that it would certainly result in a turkish victory, especially because there are times where energetic youth (and i grant you that John Komnenos wasn't anything if not energetic) wins against experience (Arslan would be much more experienced than John, even though they have only an eight-year difference in actual age), but it would be an interesting confront indeed, you might see an earlier second crusade due to Arslan finishing off Edessa and Aleppo, although things may not go so smooth due to the more established powerbase of Arslan ITTL (it really comes down to writing a TL, it could go as much for Arslan's side as it could go to the byzantine's), but indeed you have the threat of an early collapse of the Crusader States, even IOTL Arslan tried a campaign against Antioch which failed mostly because the Danishmendids didn't help much in being "allies" (this subsequently resulted in Arslan just screwing over them and forcing subjection), if you want any eastern mess the danishmendids are your bet, although they most probably would be cut down to size after any Rûm victory in Mesopotamia (and thus eliminating this credible threat).
I think of Arslan as an fairly clever ruler, after the crusaders started to go brrrrr in their promises to the byzantines he effectively allied with Alexios in order to screw over the crusaders, but his early death ended up damning these plans. Anyway, with John in power any friendly relationship will most likely go to hell because of John's energetic will, i wouldn't remove the possibility of Arslan invading the byzantines soon after the pechenegs come rolling again, if only to regain lost territories of strategic importance.
Anyway, Arslan most likely would hit heads with the crusaders as soon as they start to take over the remnants of fatimid rule in the Levant, since the isolated cities probably would declare for Arslan in the nearest opportunity. The main problem for Arslan is continuing his legacy, it doesn't really matter if he manages to become the main Seljuk Sultan, win against the byzantines in some anatolian campaigns and screw over the crusaders successively if he isn't succeeded at level, IOTL Malikshah (his sucessor) was elevated being 14 years old and at the very least wasn't really competent at all, returning in conflict with the byzantines only to be crushed by Alexios and dying with 20 years (he lost his father with 11 years and spent 3 years in captivity at Ispahan - during which the Rûm Sultanate was in a three-way civil war and the byzantines recovered a lot of territory - so i really can't blame him for not being particularly competent), if Arslan lives, let's say, to the 1130s (his 50s), i think you can get a decent enough Malikshah (especially because he wouldn't have lost the most important part of learning to be a ruler - adolescence - in captivity without a father) that wouldn't screw everything over, although i don't think he would be anything fantastical either, just sufficient to keep the train moving on, after his (probably brief, he would be Sultan with around 40 years) reign you start to work with much more butterflies.