Hi there, no I don't believe that evasion is any way easier, in and of itself, with KBM compared to dual stick, HOTAS or controller. I sometimes evade with hardpoints retracted to see how long I can keep an attacker missing for, or I field all gimballed loadouts and evade, evade, evade. You can use any control system to do those things. I see Cmdr Xpressive in this thread, who uses a controller, and Xpressive has many, many times outlasted a fixed weapon user by combining evasion with gimbals.
Where KBM becomes superior and is used in practically all cases, except by a very few skilled dual stick users, is where the contest becomes evading fixed weapons whilst at the same time attempting to hit with your own. There is nothing quite as good as the combination of FA-off and Relative Mouse for that task. If you check out PvP Hub vids like the 2v2 contest the guys had recently you'll see what I mean.
The same principles of evasion apply to hit scan as to travel-time weapons but ofc it's much more difficult, most especially because you lose the ability to be somewhere different to where the reticle said you would be.
However, hit scan weapons come with their own downsides, most particularly that they force all but the most skilled users to reduce their own movement in order to aim. Plasma is very effective 1v1 despite its mediocre RoF and DPE because it condenses damage into one brief momentary twitch trigger. Even 3 or 4 rails don't really achieve that in the same way.
Personally I have not for over a year flown shieldless or low-shield builds partly due to overall hit points but also because, as you say, a good pilot with super-penetrator or other powerful counters will hit too hard. The last time I flew my Courier with a low shield my buddy Dezpe reverski-planted me with super penetrator, and even though he is like 1 in 100,000 skill level, the fact is there is no answer to it in FdL or Courier, that can't stack MRP's, except to keep the shield up.
However, even though there are people out there a lot better than me, I can tell you truly that if I am fully gimballed (as I usually am nowadays, for a 1v1, sadly) I have never lost a medium ship 1v1 in FdL, and never lost a small ship 1v1 in Courier, since 2.1. I have a couple of times lost when I have been full fixed or in partial fixed/gimballed loadouts but never full gimballed. (Two examples of losses: Xpressive after 45 mins beat my mixed loadout Courier with the phasing on his Viper without me losing shield lol, and Dezpe beat my full-fixed multi FdL with his plasma'n'rails FdL. I can't evade properly while aiming fixed multis, sadly nobody can.) And ofc the most common build I've fought has been plasma'n'rails, in both medium and small ship categories, across scores upon scores of duels.
I appreciate that some readers might find it surprising that gimbals can > fixed undefeated in over 2 years, 1v1, but that is the truth. And it's a terrible indictment of the game because it's a combined product of the over-performing ToT of gimbals compared to fixed, with the absurd relevance of hit point inflation, which permits the gimballed user, if they don't just fly backwards 4-0-2 but instead fly evasively, to outlast chaff. Because the chaff was designed for an engagement with 20% of the hit points and modding from 11 ammo up to 15 doesn't redress the balance.
I'm not saying it's impossible for an experienced PvP-er with gimbals to lose to an experienced PvP-er with fixed (perhaps it will finally happen to me next week) but it is blindingly obvious who the odds are stacked in favour of. In fact, when I was a member of the PvP Coalition Discord (a body devoted to game balance feedback to FDev) this was something literally everyone agreed upon, including PvP-ers of the experience of Ryan_m and Rinzler, both of whom have unfortunately lost 1v1's to undeniably less skilled pilots because the latter were using gimbals.
