I've been playing RDM for a long long time as well, and have cleared all the current fights. ( https://www.fflogs.com/character/id/168393 )
I'd love to see several changes, and I'll go over them all.
Displacement
Now I think we can all agree that displacement is still terrible. Displacement punishes you depending on raid encounter. Sometimes you just can't jump due to various reasons. Think of having to stack stacking for heals, platforms being small, or just certain mechanics happening. Even though they added engagement now to counter this, engagement will always be a lesser option. Something you'd rather avoid using cause displacement does more potency. To me it is strange that they remove damage from abilities that knock you back or the enemy back (such as repelling shot, blank, fluid aura), but keep displacement in place. What I'd personally like to see for displacement: Abolish the damage and the recast timer with engagement, and buff engagement's potency to displacement's current level. This way displacement will still be a really good movement tool, but you're not forced to use it.
Impact and Manafication
Now that impact has become AoE, you have no means of recovering a bad luck opener. If you get no procs at all you'll always end up missing 1 mana, meaning your opener is delayed by a whopping 2 GCDs. Those 2 GCDs are crucial to your buff alignment, because this means your manafication will be delayed as well. That 1 missing mana was covered by Impact's 4 mana, which is just completely gone now. I also think Impact added more fun to RDM, but that's entirely subjective. I'd love to see impact brought back, or else I'd just like to see a 30s buff when using Jolt II, making the next Jolt II cast give 4 mana and be 20 potency more, similar to impact. Something simple like this would fix the issue.
Another solution, and something I'd like to see is a change of manafication. With the buff manafication gives you now you don't wanna keep manafication anymore when you're close to 80/80 mana. You wanna use it as soon as its up, or maybe delay it by like 10s to align with buffs. The issue with this is the fact that you always overcap to like 70/70. Meaning throughout the fight you'll probably "throw away" a few melee combos. I'd like to see Manafication's effect changed to being able to perform a melee combo without any mana cost. This would also be a fix to the impact issue and the general burst timing issue RDM suffers from.
Aside from that I think the damage tax from verraise is too high, but that's already been mentioned plenty of times in this thread. I just hope SE takes a look at our job, and doesn't neglect us for a whole expansion once again.
Similar suggestions the OP mentioned, but I definitely think they're good fixes for our job.