From what I can tell from the new metamagic costs, if you activate one metamagic feat:
- level 3 spells will cost the same
- level 1 and 2 spells will cost more
- level 4+ spells will cost less
If you activate more than one metamagic feat, your costs will generally be less.
While I think overall this system is great for high level pure casters, I would like to point out that lower level casters will be negatively impacted at a time when spell points are most scarce and buff durations are already painfully short. DDO already has some low-level balance problems in some areas, and I would hate to see those compounded as new players are introduced to the game.
Also, consider the bard class, which will pay more for metamagic overall until reaching very high levels (while having significantly fewer spell points than pure casters, too!). This applies to rangers and paladins as well, although these classes typically don't take metamagic feats.