The problem is that they don't give you hero moments on the sets they are part of.
Looking at Elude again, given the way the game works it does not actually improve your performance in any meaningful way or even change what you do as SR. The T9 armors that stack the same stat on top of the armor again are really, really pointless as they give such a small boost for the downsides of them. Another example is elec armor where you very well may have near capped resists to several damage types, where popping overload wouldn't actually buff you.
On a squishy character where thats all they had, or say if a resist set got elude, thatd be a totally different story as it has much much MUCH higher value.
The best ones IMO are the t9s that offer something radically different. Meltdown being a boost to offenses for a time, Icy Bastion patching holes that ice normally doesn't cover, fire and dark having tide-turning rez nukes, MoG giving you the Mario Star power up, etc. Thinking outside the box with T9s I feel would be much more fun as you then have a meaningful choice of how to incorporate them instead of them being near auto skips or mules.
Like, imagine if Unstoppable was changed to be more of an offensive/cc tool. You pop it, get some minor res/def, but also have a 3ft PBAoE around you for the duration that causes knockdown to foes as you barrel through/adds KD and some smashing damage to your attacks. Overload on elec armor grants you some res, but also a ton of recovery and a supercharged damage aura where everything around you is constantly shocked. Elude grants maybe some elusivity in PvE to counter accuracy on top of your defense, and a larger movement and recharge bonus. Etc, etc.