This is a change to Rangers' favoured enemies based on ease of book keeping, rather than for any balance issues. It's not original, having already been done in Neverwinter Nights, but I think it's better than either the old 3e/PF method.
Currently you get a +2 to any one favoured enemy, then later on you get a +2 to another second FE, plus a floating +2 that you can add to whichever you want. Each time you get a new FE, you get a +2 against that enemy, and another +2. This seems to me to be quite complicated, as you might have +2 vs FE1, +4 vs FE2, +4 vs FE3, or +2/+2/+6 etc.
Consider the alternative: at level 1 you get your 1st FE, and you get a +1 against it then at level 5 you get a 2nd FE, and your FE bonus goes up to +2. At level 10 you get your 3rd FE, and a +3 to all. Level 15 you get 4 FE and +4 to all.
Pros: less book keeping, you only need to keep track of which enemy types you favour.
Cons: it's weaker at low levels, stronger at high levels (see below). Gives less flexibility (if you want it).
Level: new method / old method
L01: 1x1 = 1 / 2x1 = 2
L05: 2x2 = 4 / 2x2 + 1x2 = 6
L10: 3x3 = 9 / 3x2 + 2x2 = 10
L15: 4x4 = 16 / 4x2 + 3x2 = 14
L15: 5x5 = 25 / 5x2 + 4x2 = 18
L20: 6x6 = 36 / 6x2 + 5x2 = 22
etc.
So, do people think this improves things at all? Any tweaking you think might make it better, or is the old system just better (if more work)? The same adjustment could work with favoured terrain too.