I don't really see the point in making seeds cost 250. If I want clothing industry, I can just buy them from first or second caravan, even if they cost 2500 and make large amounts of expensive (25 base value) clothes after that forever. If anything, make the seeds cost 10 and reduce the value of their fibre. Personally I think that plant fibre thread valued at 7 or 10 so is fine. It is only GCS silk that is normally expensive, but it is a reward for setting up a GCS farm. Regular spider silk is even cheaper than plant fibre, so if You want plants producing silk, it is OK to make it cheap. Spiderpony / GCS silk should still be superior in some way.
After getting rid of three seeds I had enough embark points to buy partial copper armour for two ponies. The biggest problem with that was that my civilisation doesn't have cruppers. Can You make it so that all pony civilisations have all parts of pony armour available?
Raw potatoes are unhealthy (for humans and pigs at least), but you can make alcohol out of them. Tough seeing as the ponies prefer carrot and radish juice to wine perhaps it makes sense to make potatoes non-brewable. All in all potatoes are uninteresting crop in this mod. Their only merit is that they grow year round, but farming in DF is so overpowered, that I usually stop farming after a few years anyway. I'm not arguing for the removal of potatoes, just that a table of crops with values, seasons, and what can you make out of them should be in the manual.
@ Souleater17:
I haven't tried the 1.71 (which is for DF 31.25), but "Fanon is Magic" version from a few pages ago in this thread seemed to work until I installed dfhack, and run stonesense.