Okay disclosure at the start, I am a raider so have rk3 spells from last expansion. Looking at the "new" spells offered with TDS I find that the ONLY one required at this point is the new harmony due to level restrictions. The gain in power of new spells is so minimal they really aren't worth the bother, why expend more many acquire a whole new set of focusing augs and foci for an increase of what? Myself I am looking at finishing out mastery of the past to eliminate fizzles then just sticking to my current list. I don't see any notable increase in power or reduction of resists with latest offerings that shout out that I just gotta get me some of these.
Between focus decay and type 3s, sticking with old rk3s for a while is probably correct. I also like to wait till I'm able to fully use the new spells to remake my spell sets, so I don't have to make intern spell sets with a mix of old and new spells. I have my dirty New Raids set and that's it for now.
With focus decay, I usually stick with lower level spells until I get my raid focus effects and, for some spells, rank 3. The only spell I have gotten so far is the new harmony, because I needed it to pull on Brother Island.
