I am less interested in the damaging versions of the reserve feats than in the utility versions. I'm especially interested in their use by multiclass or non primary spellcasters.
...I should explain my reasoning. Sorcerors hardly need more spells per day. Wizards? They'll get some benefit, but not a ton at higher levels, especially for the damagine attacks that dont' grow incredibly fast.
Nonprimary spellcasters often have significant limits on spells per day. For example, a hexblade runs out of spells very, very quick. These feats could give them permanent magical natures to augment their abilities. Reserve feats that look good for hexblades: Blade of Force, Dimensional Jaunt, Dimensional Reach, Face Changer, Magic Disruption, Minor Shapeshift, Sun Light Eyes, Wind Guided Arrows.
I don't have the actual text of these feats, just the preview in this thread. But all of them look fun, useful, and thematic.