For new characters, a reasonable chance at obtaining them (not guaranteed, but not 0.0001% or spend 7,000 ironite on 75 event souls - something around the 2,500 ironite mark would be more accessible). I've nothing against them selling talisman sets for real money as long as they then become available at a later date through IC/FC/Gauntlet/other events - paying to get something early is fine, paying to get something that's exclusive can be annoying. I like the new Dungeons they've started doing as they offer a bit of variety. Grind events can be tedious if the objective is to do thousands of effects that are only possible via a rare talisman set and, even then, having a 35% chance of triggering, so moderation in planning these so everyone can take part is something that ought to be considered.

Basically, whatever the new content is there ought to be a substantial chance that any regular player can achieve it - thinking along the lines of people who play all their Troopers every day as a bench mark. Not that everyone will get everything, but that it's possible to get things without spending a ridiculous amount of resources/real money.