What if Outposts cost 50 Wood, but no Stone, and took longer to build?

Outposts are not seen all too often because no one likes spending Stone on them. Even if they were to cost 1 Stone, that'd still be too much because it'd stop you from putting down 2 TCs without mining any Stone. Add on that players often use Houses instead of Outposts for LoS purposes and it's sometimes hard to justify making them except in a Deathmatch.

Now imagine that they were changed to cost 50 Wood, no Stone, and took longer to build. Would that be a good change?

Personally, I think it'd be a very good change, letting you more freely use them without making them spammable. The higher Wood cost would hinder you if you don't adjust your economy properly, and the increased build time would also hurt you economically by forcing a Villager(s) to spend less time gathering. As such, in high-tier play, you probably still wouldn't spam them, as that economic hit could come back to bite you. But in exchange, you'd be able to build Outposts without worrying about Stone costs.