someone from the official site gave some suggestions that metamagics don't stacks at epic levels. Instead, if want to combine two or more times of the same metamagic you have to buy it twice.
It's a variant rule suggested in a recent page on wizards page, along with the vairant epic level instant death rules (20d6+1d6/level on a failed save). It's not the deafult rule.
well, i just want to know some opinions about that, i don't really think the system of magic needs a fix,but the spells and spellcasting classes do need.
Today i think the most important factor to help balance wizards with clerics is the metamagic system.