I am puzzled, My Warden Solo's just fine at 51, Whites are fairly easy, and I can take down a heroic blue. Does this change in latter game.
What I will say is I have no spells under APP3 and most are masters. I have strong gear based on wis and Int. the int is important as it controls the amount of damage your spells do.
I solo mostly, though do enjoy grouping I have some days when my reflexs are not up to grouping so I solo. Maybe because I solo so much, I am either used to it and know how not to get killed or my skills are maxed on hand to hand and defence or maybe its just my spells are so high they make the differnce. When all your spells are that high it helps.
So how do I afford such things... Harvesting... I harvest when I solo, good for a couple plat worth of rares every couple days. with that, its easy to get better gear and spells.
Now I am unsure if 52 to 70 becomes impossible to solo, I doubt it.
I keep my spells as high as I can get em, then worry about my gear. true they cycle, but then I am buying upgrades for the others.
My gear is nice too, get all the cool stuff when I do group and stomp around in a dungeon.
Not worrying about your spell level seems foolish, thats like running your warden at 25% efficiency
Your spells are everything, to you and your group.
but that is my opinion, I am a far cry from an expert.
But I will say I kick some baddy butt :) and have allot of fun doing it too