I think that the E5+ requirement is because they monetize in part by getting people to advance and level, buying cache keys and other upgradey parts, or otherwise spend lots of time in game. It isn’t likely that will change much.
But lets be honest, the rewards cater to people who stay in the game longer, and help with the incredibly long scenario grind. Story wise, they are sidestories, and offer a glimpse into another part of the secret world that the main story doesn’t particularly touch on, nor the PVP any longer. And as we know from TSW, the general population doesn’t care much about sidestories.
So if someone only cares about the main story and isn’t going to play much beyond that, they aren’t really missing anything here.
Now as some folks are bringing up cruel delight and such, I need to point out that CD is not remotely effective without having put a lot of time into scenarios to get your crit rate up high enough that is reliable, and to level the signet to the point where it makes a real difference. Red levels are approximately required for that to be true in E10, which is a huge amount of effort put into the gear.
Furthermore, I can at least self attest that my cruel delight and anima touched weapon are the entirety of my self healing for scenarios and these new missions. Were I to need more than that, I would have to change my AA from full DPS to something else, and possibly swap out DPS abilities for healing ones.
Might that make things more interesting? Sure. But what is the net effect? It now takes even longer. That doesn’t actually help in the end. There is no ability for me to speed up the fight and do more damage. I already do as much as I possibly can, so forcing me to rely on more healing/tanking means I end up spending even more time in those fights, which is even less exciting.
I don’t know how other people run these missions, but I dare say that would be the same for most people, that making CD less effective would only make it worse without a more dramatic reduction in enemy HP to counteract that issue.