Writing on another thread got me in a mood to discuss this, so here goes. Personally I have always liked the mechanics behind seed magic. It gives a great deal of freedom and room for creativity. IMHO it’s the best section from the epic level handbook (other than the art and monsters, you can never have too many monsters >:) My only complaint is that it seems like too much power too quick. As soon as you hit level 21 you buy the feat and kaboom, you are suddenly endowed with far greater ability than you had before, just add xp. This comes to my second complaint which is that the wizard epic level progression is really weak. You get no more spells per day, no new abilities, no increases to saves, just a few bonus feats every once in a while (do you still get two spells per level?). In other words, there is no compelling reason to get more wizard levels once you hit epic as they really give you nothing a prestige class wouldn’t (and even those seem a little anemic).
My next thought is that maybe you could kill two birds with one stone. Get rid of the seed magic feat and turn it into part of the epic wizard progression That way you would be adding seeds as the wizard grew in understanding and power, which I find to be far more reasonable than sudden massive jumps in ability. Also the epic wizard progression would be a lot more interesting this way. As a bonus you would see real diversification between epic level casters depending on which seeds they picked.
As always I would love to hear your ideas and opinions and about any experiences you may have had.