This is the Imladris subsection of my gameplay & balance post over at the general balance discussion thread.
Imladris eco upgrades seem too strong. The cost and buildtime increase could be reversed. Imladris could unlock erestor when building the library. Bringing the library to level 2 could also bring the economy and military structures to level 2 and upgrading the library to level 3 could bring everything else to level 3 as well. Currently the library is never upgraded to level 3. By making this necessary for the economy it might also incentivize using the never used veterans of the last alliance, wind riders, imladris archers or loremasters because you unlock their upgrades now anyway at some point.
Imladris is by no means overpowered however, their battalions are very weak when isolated and trapped making map control for them extremely difficult.