Are bot throwers worth there pionts, or do the new artillery rules makecannons and stone throwers so good that the bolt thrower is now crap?

Bolt throwers are still good they still allow no armor saves. Crazy good.

And with lots of ranks now easy to take down tons of guys

Its a wash. Remember that stone throwers, while slightly more accurate now, also are only S3 and allow saves. So while they hit more you get saves which is about the same for low AS troops, but a huge win for high AS troops.

Cannons wash as well. No guessing, but you still have to roll adjustment and bounce, so it only helps those people that were bad at guessing.

Bolt Throwers work the same, but with more ranks and true LoS they are still very useful.

The only drawback is that you can now wound everything on a 6+, and the wounds are the crew, so war machines are very susceptible to being shot out. You only need to roll 2-3 6's to destroy a machine now.