Outright nerfing extend to no longer work with a massive variety of offensive spells (nearly all of them, tho not quite all from what I saw) isn't a good solution to balance casters.
Nor is what was done to enlarge.. Free enlarge for select spells making the feat even less desireable? (which was already a very rarely taken feat at best)
And some key savant enhancable spells are even missing maximize/empower as options.. That's the worst - especially since elemental savant 3 makes you further enhance those feats as enhancement requirements.
Some examples that should be looked at:
Wall of fire/Incendiary cloud/etc.. All persistant AOEs that deal damage:
Should be extendable.
We get that you want to balance there dmg output totals against there sp cost. But you can do that without nerfing extend. Just drop there duration to half of what it is now (so 15s for firewall) then enable extend. Tweaking the SP cost to match may be nice too, but either way I'd pay the extra SP to avoid the nerfs and keep the game balanced.
Free enlarge on ray spells:
I get that some players have problems landing these.. But why is the solution to just nerf enlarge? Seems like "better tracking" fix alone would of done the trick. Personally I can never fit enlarge into my builds, so it's only a bonus to me... But still don't like it, all meta magic feats should be worthwhile. I guess the ideal solution would be to keep some of the extra range on them, but let enlarge work to make them go even further - but I realise this would be tough to code. Probably low priority.
Atlernative fix:
Since enlarge is a feat that is near impossible to fit into most good Sorcerer builds (and sometimes wizards) why not simply make it an enhancement instead? Could just be an expensive enhancement: Say 4-6 AP and works as is. Or cheaper free version per spell line: Say: 2 AP to free enlarged rays, 2 more AP for enalarged CC spells, 2 more ap for enalrged aoe direct dmg spells. Would be better then just plain "free for everyone, for ray spells"
Spells just plain missing maximize/empower as options that could really use it:
Cloudkill:
Since this is one of the KEY earth savant spells and deals firewall like damage - it really should be maximize/empowerable. It's not like you would be creating a very broken spell like wall of fire tended to be.. As it would still be inferior to wall of fire due to the fact that massive amount of monsters in the game are immune to it (Anything immune to poison = immune to its acid dmg also, which includes every red/purple named in the game)
Contagion:
Well max/emp stat dmg may be overpowered. But since the "slimy doom" portion was changed to straight acid dmg, that should be max/empowerable, as well as correctly effected by enhancements. May be tricky to selective set sub-spells as max/emp enabled, but if you can. Turn it on please.
Well the metamagic on/'off pass wasn't all bad at least.. Some good changes:
Mass hold no longer extenable:
This is good because with a base duration of 2min, and recurring saves every 2-3 seconds.. It was ultra unlikely that it would ever last over 2 mins, no matter how good your spell DC.