My only issue with this mod-pack thus far are the 2nd-tier of tools from Tinkers, The Hammer, Lumber axe, Excavator, etc. To me it feels way to easy to obtain early on for tools that totally throw your production through the roof. Having the excavator at such a low cost also renders the earthmover Shovel from Thaumcraft a moot-point, although the TC shovel can place what it digs up. A possible solution would be to make the patterns for the parts of these tools an earned item, or found in treasure chests, as using Iron blocks to make the proper tinker table for them is still not much of a limiting factor.
And I can agree with the idea that the 2nd-teir is a bit to easy. But this should matter little in SSP as you can opt to just not use them until you feel you is right.
But there are also other ways to as you put throw your production through the roof. Off hand turtles being the most obvus cheap and easy setup that you having running before you got to teir 2.
Found items as a gating system for tiers IMHO is the worst way to do things. Random is Random and it can screw over players. What would be better is cost for either the teir 2 patterns or tier 2 table to go up. but sadly those rarely are ture gating systems and more just added grind.
The best balnce for many mods you feel are OP is self control. Unless we are talking about infinate loops or the such.