It would puzzle me if someone like the warden stayed out of the events that unfold in DA2 and DAI. Imo he/she is too important to not at least have his/her assistance requested by someone.
It makes sense really. The events of DA2 wern't huge world changing events on the surface, but smaller ones happening and building tension which is what led to the finales of Act 2 and 3. Rites of Anullment and skirmishes with the Qunari aren't unheard of either, so there's no reason to assume it'd turn out as it did.
On top of that, they are a Grey Warden. Unless it's to do with the Darkspawn, it's not there concern and if Stroud/Alistair are to be taken at there word, something is going down with the Grey Wardens and The Warden is probably involved.
A big whole in the sky threatening to eat the world on the other hand pretty much demands everyone chip in and help prevent it.
Why would Hawke kill Petrice? S/he's not a sociopath. You can even tell Elthina about it early on and she does jack about it, just like she does with the Mage/Templar problem.
At what point would Hawke stop Isabela? I'll admit it's been a while since I've last played it, but if I recall, she asks Hawkes help in getting it and the buggers off while in a different room. Either before Hawke knew she was after it for herself or before he could convince her to change her mind.
No, the act 2 finale isn't a war, it's just a sacking of a city. And no, Hawke wasn't the one to bring the Lyrium Idol to the surface. Batrand was.
Either way, you're blaming Hawke for things that weren't in there control. It'd be like expecting The warden to know how to take down the Blight without the treaties and Flemeth, Alistair and Riorden there to give them vital information, then calling them rubbish because the armies had no obligation to help and they didn't know they had to make the killing blow.
Moving on! What would you guys say the likelihood of The Warden having a chance to talk to Leliana, Morrigan and Alistair if they romanced them? No Zev unfortunately 