Homo sum: humani nihil a me alienum puto. - Terence
My M2:TW 4TPY Script, Adapted to Work With Hotseat.
Guides and Useful Posts of Mine
Middle Earth Strategikon (M2:TW: TATW 3.2)(WIP: ~60% Complete)
Advice on Playing as Gondor - Part I - Part II (M2:TW: TATW 3.2)
Dirty Secret to Killing Trolls Fast and Easy (M2:TW: TATW)
The Basics of Naval Engagements Part I - Part II (EMPIRE: DMUC)
Roman Army Composition and Use (RTW: RTR Platinum)
The OP was about Silvans vs trolls. Silvans absolutely shred trolls with their mid level infantry... ESPECIALLY Woodland Warriors but even Forest Wardens will get the job done fine. You have to think of trolls in terms of dollars... they cost 2x-3x as much as a unit of infantry, both to train and maintain, and they have very long training times, so it's fair to commit 2 units of WW to fighting them, in which case the WW win handily. Any armor piercing infantry is amazing against them, but even basic infantry can get the job done if they surround the trolls.
The main "problem" is that a Silvan player will be accustomed to kiting orc infantry with 100:1 kill ratios, able to saw down stack after stack from Mordor, and the speed of trolls actually forces you to engage the enemy rather than kite them which feels more difficult.