1. When leveling up, it would be nice to back points out. As it stands, you are stuck if you make a mistake.
2. It's pretty complex figuring out how to build your characters. Having someone with Pet Pal is important if you are into the story aspect.
I don't think you're ever really stuck in this game, as far as having a character that's able to complete it.
The concept of re-speccing is always a tricky one. While I always think that I would prefer a system that let me make minor changes often as you suggest, as opposed to wholesale re-spec, I feel like it would be pretty exploitable in this game. For instance you mention Pet Pal, an ability that is situationally useful, but not as useful as other perks that pay dividends much more often. What's to stop someone from swapping out that talent to use for those specific situations, then swapping it back out for a more general purpose one as soon as it's not needed?
I think players should have to commit to choices, and try out different things in replays. Re-spec is probably always exploitable, but probably a necessary measure to appeal to players without as much time or patience. That said, I think it should be a rare occurrence, costly, and not something able to happen casually throughout the game.