So my critique of a system like that is that having skills scattered all over the place from +1 to +11 is unnecessary. The difference between +9 and +11 is also not noticeable. Just have two settings per skill: unskilled, and skilled. "Skilled" gives you +10 (or whatever).
You certainly could just have 1-2 levels of skill with a sizable percentile performance gap, and that would be differentiable. I do personally think there's a benefit to the granularity of skill investment though.
"Should I choose +3 and +5, or +5 and +3?" The +5 conveys the idea that you are better at one skill than the other, but it doesn't really matter.
Here, I agree, if all your skills are progressing at a similar pace, or two-tracks, this doesn't particularly matter. You could have the half-progression track and the full progression track; or 1/3 and 2/3, or whatever - though even here, there's a bit of a benefit to the granularity: you
can progress all your 'full-track' skills at a pace a little slower than full-track in order to squeeze in another skill and be almost as good at all of them. If you have 6+int skill points and a +0 int mod (ranger), and say you don't care to do anything fancy, but there are 8 skills you want; At level 1, you have +3 in everything instead of +4. Then every level thereafter you only advance 4 of your 6 skills in ranks, rotating which ones you advance. Giving you 8 skills which are all at 75% ranks progression (plus whatever you invest in gear, synergy bonuses once you get them above 5 ranks, etc). The granularity gives you the freedom to make a slower advancement track to be a bit more of a jack of all trades and have more skills that youre good at.
The difference between those two approaches....and this is the thing I've been trying to argue all along...is that the granular system, adding +5% (or similarly minor) adjustments at a time, mostly just serves to satisfy the craving that some players have to fiddle with character build.
But here's where I disagree more tangibly: (in 3.x - less so in 5.x with its wishy-washy fuzzy-fiat DCs)
Consider Ride: The mechanics are fleshed out. If all I care about doing with it is ride a trained warhorse in combat without falling off if it gets spooked or either of us takes damage, and I don't need ever-increasingly athletic horsemanship tricks, once I have a +5 in the skill from any of the sources that could give me a bonus to it (and at least one rank); I never need to increase it again. That could be as simple as 1 rank in ride for +1; 5 ranks in handle animal for +2 (if I need it for something else); and a +2 dexterity modifier (
or a suitable masterwork saddle for +2 instead of one of the other options for a +2). I will never have to roll to stay on the horse when I get hit. Put a couple points into ride training, buy the nice saddle, and you're done - congratulations, you can ride a horse.
The other skills are full of similar examples. Once you hit the skill bonuses needed for autosuccess on the things you care to do with them (or to hit the tedious prerequisites of some feat or prestige class you want), you can stop investing in them entirely to focus all your training and money elsewhere; allowing you to be "good enough" at the things that are less important to you to not have to worry about it, and really good at the things that matter to you.
By way of autosuccess thresholds via math and benchmark DCs, the skills serve as perk-tracks (like Skyrim perks) you can advance in to get a growing categorised list of things which you just do, without risk of failure. Once you get the perks and roll modifiers you want, you can stop advancing in that track.