I'm playing around with a warden now, I'm not an expert yet but I should be able to help you.
Postman wrote:
1 - Are wardens now fight with long weapon in one hand and knife in another?
2 - Can they use shield?
3 - Can they join anti-magic faction?
Some guide about talents and desirable paradox level would be welcome, especially as talent description is more difficult to read now.
1 - Yes, perfectly viable although you won't probably want to dump too many talent points into this unless you're going specifically for a melee build.
2 - Yes, but there are no talents to benefit from this, so there's no advantage to it. A slimy dagger is better than any shield you can get.
3 - No, you'll get all your skills disabled so it'll ruin your character.
About paradox level:
You get failure, backfire and anomaly chances starting at 200 (increased a bit by Willpower), however the backfire and anomalies aren't that dangerous most of the time. Your biggest concern will be your spells failing and losing the turn.
Recommended resting paradox level is somewhere around 200-300 depending on your Willpower, however you are perfectly capable of fighting at 600ish paradox at limited risk.
Just remember that your time spells have a failure chance so don't save that dimensional jump for the last possible second or Murphy's Law will get you.
About talents... Echoes and Time skip are great. Damage smearing is much better than it seems at first, and the ranged talents seem to scale much faster than the melee ones, so you might want to change to archer mode later on.
Static history is a necessity but you can live up to mid-game on one talent.