I disagree, but I'll grant you this for the sake of argument.
Yeah. My meaning was along the lines of "If you are set on changing the fighter, this is what should be changed". Basically, if you need change, don't give more power, give more options.
That's definitely a more interesting approach to me.
(FWIW, I don't think your sequence is growing quadratically...)
I just kind of tossed that in there as an example. Those would have been every odd level (1st, 3rd, 5th, etc). You can make it quadratic if you want, but as long as it's getter bigger increases each time, it's giving a non-linear set of options.
This definitely removes the fighter as a choice for the casual gamer and pushes it towards "hard core;" i.e. the assumption that what fighters really want is the same book-keeping exercise that wizards go through every day.
Call me skeptical.
But again, I do appreciate your approach.
While the Wizard has a lot of bookkeeping during the game to optimize, the Fighter needs a lot of bookkeeping and research before making his choices to optimize.
In my experience, Fighter's are not that user friendly, for the simple fact that once they've made their decision, they are stuck with it... even if they find out their decision was a poor one, or that the game changes drastically enough at the higher levels to make what used to be a good choice into a poor one.
Giving the Fighter more options like this would actually make things easier for new players, as they'd have more room for error (instead of picking 10 feats and be stuck with it, they get 40 and can use the ones that are working for the situation).
True, it's a bit more bookkeeping, I can't deny that. However at 12th level, deciding which tree will be useful for the day shouldn't be tough (am I fighting mages? flying creatures? should I specialize in ranged or melee?).. they are pretty easy questions compared to the wizard.
It moves agonizing over what will be useful at the beginning of character creation, and then getting stuck with that, for better or worse... to humming over which tree will get the most use today, and if you were wrong, well you can change it again with a day's rest.
That's the key factor...