If you work in 3039 Variants like the Mirage (Firestarter-M) Jenner-F Those move right to the top. Firestarter-K with the Large Laser is an effective energy "sniper" (PLUS: Still has the Jump Jets) Firestarter-A does almost everything the H does but is tougher. Does run hot.
Locust 3E and 3V are solid even the 3S has a place.
So working in variants changes your list. In some ways, quite a bit.
Also, we aren't looking at roles here beyond combat effectiveness. In Lore, the Ostscout is considered a real prize and only the best scout pilots are assigned to them.
The Valkyrie is not usually assigned to scout lances and shines in working on slower units where the LRMs can do real damage. Vs Lights or Fast mediums the LRMS hit so infrequently that the power as an LRM platform is wasted. Then again, in Lore, LRMs are often used as suppression weapons, where no rule for that exists in game.
Wasp-W (with all the small lasers) is interesting if Niche. I've used them to annihilate lights and cause terrible damage to anything it can jump behind. They don't live long however.
Urbanmechs are solid in their environment and quite good as Vehicle escorts. Hornets can behave in a similar manner but without the good gun. Having a unit that can move late and kick an enemy looking to melee a tank (or early and leave your BFG tank to move last) is VERY effective. Especially if you can reasonably cause it a PSR to fall and then get kicked. Sure it's just 6 points of damage from the kick. No light enjoys that sort of damage, even mediums are threatened if you dropped 20+ into it and now kick it. (Or Kick it after shooting and now that mech is on the ground at the start of the next round)
Gotta look at role and think outside of the Mech vs Mech slugfest. Unless that's all you do of course.