No I think its a good idea, thats what martials should be able to do in core it would solve alot of problems.
Fleet Warrior is a pretty awesome ability. Personally, if I were running a game and wanted to make it available to my players as a non-mythic ability, I wouldn't change anything about it and would just make it a feat expanding on either Spring Attack or the Step Up feat tree:
Fleet Warrior (Combat)
Prerequisites: Dex 15, Dodge, Mobility, Spring Attack, base attack bonus +6.
-or-
Fleet Warrior (Combat)
Prerequisites: Dex 15, Following Step, Step Up, Step Up and Strike, base attack bonus +8.
-or- (if I was feeling more generous)
Fleet Warrior (Combat)
Prerequisites: Dex 13, Following Step, Step Up, base attack bonus +6.
As for Weapon Finesse (Mythic), it's probably a little too good to just make it non-mythic without anything else. Again, if I was running a game, I'd be okay with this:
Improved Weapon Finesse (Combat)
Prerequisite: Weapon Finesse, Weapon Focus.
Benefit: When using Weapon Finesse with a weapon for which you have the Weapon Focus feat, you may also use your Dexterity modifier instead of your Strength modifier on your damage rolls. If you carry a shield, its armor check penalty doesn't apply to either the attack rolls or the damage rolls.
I really like the weapon focus requirement for improved finesse. And I think I prefer tying fleet warrior to spring attack makes sense. Kind of the ultimate mobility option.
Fleet Warrior is a pretty awesome ability. Personally, if I were running a game and wanted to make it available to my players as a non-mythic ability, I wouldn't change anything about it and would just make it a feat expanding on either Spring Attack or the Step Up feat tree:
Fleet Warrior (Combat)
Prerequisites: Dex 15, Dodge, Mobility, Spring Attack, base attack bonus +6.-or-
Fleet Warrior (Combat)
Prerequisites: Dex 15, Following Step, Step Up, Step Up and Strike, base attack bonus +8.-or- (if I was feeling more generous)
Fleet Warrior (Combat)
Prerequisites: Dex 13, Following Step, Step Up, base attack bonus +6.
The feat tax is strong with this one. Seriously. Not only that, but this whole feat chain suddenly becomes mandatory. If you play a class that swings an inanimate object to hurt other people then you have to have this feat chain.
Going the feat route for this is probably not the right way to do it. Melee are already pretty far behind casters and eating up all their feats is just going to hurt them in the long run. Even if the feats are pretty decent or useful it robs them of flexibility and originality.
This needs to be baseline somehow. Like an edit of the basic rules of melee combat. Essentially make the full attack action a standard action is what I'm getting at. It would be a sudden power boost to melee, but it's really only a boost to their opening round. Once a fight gets started most people plant their feet and move as little as possible. This change would cause combat to become a lot more mobile. It would also cause people to focus more on defensive abilities, armor, and defensive feats.
Yes, I wrote them with a heavy feat investment. Based on what the ability does, it felt warranted (it is a 3rd-tier mythic ability after all). Personally, I don't find it to be much different than someone being a ranged fighter, especially if you're going thrown or crossbow. In my experience, Quick Draw/Rapid Reload, Point-Blank Shot, and Precise Shot are required for such a character. On top of that, most characters would also want Rapid Shot and Deadly Aim. The third option is also 3 feats and since the only big level based limiting requirement for that option is +6 BAB, it's not very late entry since that's when you get your first extra attack anyway (unless you go two-weapon).
Again, that is just what I would require if a character wanted such feats as non-mythic options. I've never actually ran a game before beyond a few one-on-one sessions with my wife, so take my option with a grain of salt. Personally, when I really get into GMing, I see myself almost always utilizing Mythic rules, so this isn't really an issue for me anyway.
If you want an option that isn't feat intensive, I'd say try to use Gunsmith's full-attack = standard action option. It will invalidate a lot of things in the game so it would require a good amount of work, but it seems like fun. And it might make martial classes a little more balanced against casters. If a 6th level wizard can throw a fireball at a mob doing 6d6 of damage to everyone in range as a standard action, why can't a fighter of the same level attack twice as a standard action?
But if you aren't typically the GM and you're thinking of trying to convince your GM to let you get this ability in a non-mythic campaign and therefore need something that is balanced against the current rule-set, I think the stupid feat trees are the best I have without making a lot of archetype trades or getting magic items or something involved. Sorry.
If I was to integrate fleet warrior, I would probably try to integrate it in a similar way to "best totem", IE at least 2 requirements. What they would be though is hard to say.
Although I dont think simply having "bab+11" would be too little a cost. Move+ full attack shouldnt be so costly in my mind..0.
Also: for weapon finesse, I include a second feat that allows dex to damage for any finessable weapons, with minimal requirements. Havent seen anyone take it yet, but it's an option I keep available.
I had a similar idea, but with a catch; my feat version FW's only prereq is to have BAB +6, and only that.
Am I a little too generous?