By now, you all know that nearly any primary spellcaster worth his stripes will eventually finagle their build to incorporate the Dazing Spell metamagic feat (+3 to spell level - unless you get a magic MM Rod). It doesn't matter if you are a spellcaster who emphasizes BC, buff/debuff, blasting, summoning, etc. .... Dazing Spell is the "I Win!" button for spellcasters. Because nothing is really immune to Dazing.
Personally, I don't use it on my spellcasters. For the same reason I never used Incantatrix in 3.5. And because DMs using it against my group can be utterly maddening. Since I don't like to use the word "ban" (woohoo!), I will say that in both my tabletop groups we decided to stop using Dazing Spell via mutual DM/Player Gentlemen Agreements almost as soon as it got popular.
But this is where it gets good.
The breadth of spellcaster styles, patterns and theme builds has greatly expanded. I rarely see It's funny how that one feat, as much as it was sorta well-balanced cost-wise, just absolutely dominated the buildcraft scene and pretty much handcuffed most casters into taking it. As a result, there's no real "must have" feat or class feature in primary spellcasters any more (we're ignoring pre-Unchained Summoner/Eidolon combos in this talk). So the variety is pretty cool now - and lots of creativity in build chassis crafting.
