Not to debate the point too much, but there are a few things I'd like to note that you seem to have ignored or missed.
- Dimensional Lock prevents teleporting out of the force cage. Or using Etherealness or Dimension Door or anything of the sort. Dimension Lock does allow Spell Resistance, but other than that, the combination of those two means that you can't get out without destroying or dispelling one of the effects. Period.
- As for being guaranteed to get more than two rounds, thus the maximized Time Stop.
- As far as maximizing Time Stop goes, that's what a metamagic rod is for. 3/day maximized is significant and guarantees you the time you need.
- As for Black Tentacles, I'm not in the slightest concerned about the rogues and the fighters not being grappled. The Tentacles aren't for them. The tentacles are there to prevent the casters from getting rid of the Forcecage and Dimensional Lock.
At any rate, yes, there are a number of ways to get around the scenario there... but the point is, it's far, for more dangerous than a
Meteor Swarm that does a chunk of d6s. Even if you use the same metamagic.
rod to maximize the Swarm.
As far as this, that argument is essentially that "if you house rule Time Stop to not be as powerful as it is, then it's not overpowered!" which is entirely true... and also completely irrelevant.
On-Topic
At the risk of being crazy and actually responding the original poster, I like the idea of a "Vancian Anchor", even if the term is a bit inaccurate. Of course, I'm the type who's all for spellcasters being capable of more powerful effects than nonspellcasters, with commensurate penalties and costs for doing so. I like my magic to be deadly not just to the targets, but dangerous to the caster, as well.