It does seem a shame that Odo's been removed from the Dominion; from what we saw in these books, he had been making true progress there, even if it wasn't on the scale he might have wanted. Perhaps the very fact that he's switched his focus from changing things wholescale to just encouraging a sense of community where he can demonstrates that one person can't be too important in the grand scheme of things, and life will continue on without him just fine. Still, it's undeniable that Odo is overwhelmingly the source of, and the driving force behind, any new perspectives that have seeped into the Dominion over the last eight years. Now that the Dominion is in isolationist mode, I hope it has enough "philosophical essence of Odo" to keep working changes, and absent the fresh injection of outside ideas won't just "shrug the effects off" and fall back into the old patterns it had just started to subtly move away from. I wonder to what extent Odo's ideas have rubbed off on the 27 other changelings who returned? I would say "I'm sure they'll keep to the isolationist policy, because Founders are like that" but given that these were the ones who returned, it might be that they're the ones particularly driven to seek out connections with others, so maybe they'll turn the Dominion's eyes outward again. Either way, I hope Odo's removal doesn't cause the subtle process of change to wind down.
The idea of a primarily Laas-influenced Dominion is rather alarming, I think; not because I think he'll attack anyone but because he'll get so frustrated he'll probably leave in disgust and go be a rock somewhere. When the Vorta run to him and start telling him that "solid race so and so is in dispute with solid race whatsit" or "production of monoform thing #36 is down", he'll just get angry and unhelpful. The Vorta would end up having to work things out for themselves anyway. It's not good when your society depends on Word From On High and that Word is "I hate all of you and can barely tolerate your existance".
That said, since the Founders are very hands-off anyway, I imagine the Dominion could continue ticking over for quite some time without any Founders at all. It would, I think, mean an increasingly desperate and panicky awareness among the lead Vorta that they don't know what to do, but I guess it would take some time for problems to pile up to the point that Dominion society starts to notice, or things are no longer running smoothly.
Basically, this is my rambling way of saying "I hope we revisit the Dominion again".