Seems to me when it comes to trading objectives, Baron is almost always superior to elder, partially due to how much longer it lasts. IMO the only time elder drag is better is if
A. the enemy team has no turrets B. your team has a ton of dragon buffs already (probably at least 3)
Those two scenarios don't come up very often, therefore I think the gap between baron and elder should be closed a bit.
I think the elder dragon buff is simply too short. You get elder, you base, then by the time you get back to the enemy base to force a fight the buff is 1/2 to 3/4 gone.
Maybe if elder buff gave sufficient hp and mana regen, or even if he just gave a huge temporary boost upon leaving combat after killing him (i.e. so a fight for elder isn't immediately lopsided for whichever team gets it, but if a team gets it uncontested they guaranteed don't need to base) then it would seem better. Although you often still want to buy.
Even just 30 seconds longer would make a world of difference on elder. The way it is now the strategy of just "turtle and stall 2min" is way too easy to use, unless as you said the team has no turrets. Which basically means they're probably going to lose anyways.
Although i do think baron should still be better than Elder. A team that's behind shouldn't be able to freely trade the two massive objectives. It would make it too hard to press an advantage if the enemy team that's really behind but has 2 good damage dealers can kill elder while you take baron and neutralize your effort.
