Might as well chime in.

What content has gated you, and for how long?
T5 but my group has barely started on it. Titan EX, have not tried it more than a couple times.

Why are you stuck here?
I absolutely cannot dodge weights on reaction due to my latency, even with vpn on. On titan HM alone I have to memorize all the patterns and then run far far ahead of the plumes alone as a dps. Titan EX looks to be even worse and the go to strategy seems to be stacking for plumes, which i might not be able to deal with (I need to run free for this). I've been avoiding the fight because I dont need any accessories from titan and ifrit ex and the weapons would just be for my alts. It's an incredibly unfun fight for me compared to just about every other fight in the game.

Are you upset about this? (if so - why? and how can content be added for more hardcore players such as myself without upsetting you.)
Dejected, more like. I can clear titan hm with much more ease now, due to being overpowered for the content and can focus on just not dying from dodge mechanics but it looks like I'm gonna experience those days again.

Should any changes be made to the content to accomodate you and players like yourself?
Uhhh.. reduction in weight plume size by 10-15%?

What kind of content would you like to see added in future patches for you to enjoy?
Less titan-likes. Coil mechanics on t1-t4 isnt so focused and punishing on latencies so I'm fine with that. CT's difficulty is a bit too easy for 4-8 man. But for some reason the dodge timings in CT is perfect for me though. I can dodge the last boss's aoe attacks as melee or ranged by reaction just fine.