Well put and for the most part spot on. One distinction that should be made though is Titans are fine in 6s and against low skill opponents but there is a massive gap at the high level.
The biggest problem is neutral game design. You mentioned it. All Light Titan sub neutral games are either one-dimensional (Bottom arc and top void are purely melee focused) or revolve around the concept of getting hit or kill with an ability procs “X” buff. Titans need cool perks built into their neutral games that have nothing to do with abilities. Only sub that really has that is middle arc with Inertia Override. Look at how the popular light subs for the other classes all have perks built in that have nothing to do with their abilities (Flawless Execution, Icarus Dash, Pulsewave, etc)
I definitely agree here. I've been maining Titan since right before Warmind came out(been using bottom tree Striker with Dunes before any buffs were made).
Much explanation down below:
[spoiler]Titans are honestly one of the best options for pubstomping in 6v6 with so many different builds available.
But in smaller team gamemodes where there are less distractions, a bigger emphasis on individual skill, and the differences in talent, skill, and experience are usually less pronounced, Titans see rarely any play in the most successful teams outside of when Antaeus Wards, Ursas, and OEM were all blatantly broken(and Behemoth recently, but I think that's honestly Stasis in general).
This is especially the case in the scrim subcommunity(s), where people generally only use the aforementioned build I listed earlier above this spoiler if they're on a Titan.
This is probably because it has the most consistency via Knockout, Reversal, and Dunemarchers having such great synergy and high potential uptime in CQC(since no melee charge is required), despite typical melee play being much less important, as well as very easy to punish in those lobbies; and also since Knockout makes killing Supers much more feasible to do.
The other subclasses are really only put into play if that specific person is what you could call a "diehard main" of them, though it's usually one of the Sentinel trees.[/spoiler]
I think Titans will always revolve around melee in some fashion at base, but some tuning to the jump abilities and another Exotic that compliments neutral game or general gunplay(that[b][i] aren't[/i][/b] exceedingly gamebreaking for PvP in an FPS) would help break away from that.