The AOE of Entangle is a problem as often times it is nigh impossible to avoid Entangling some of your party mates.... a smaller area of effect...say Grease size would make the spell much more useful.
As it stands I see this spell being used as a means to delay enemies from reaching a certain point, as a retreat tactic, and only very rarely have I seen groups coordinate to use this to pin cushion enemies. The spell falls under the Evard's Black Tentacle list of spells, fun for the caster to use but the spell caster's use of the spell is mitigated by the social and group nature of the game.
Perhaps some other people's games are not as socially conscious as others...hmm
Nail, you played a Mid Level Druid awhile back if memory serves correctly...did you feel at that time the spell was overwhelming?
On the surface I would say Entangle is less dangerous than Sleep or Greater Slumber...but the utility for Entangle lasts for more levels. On a personal level I have a fondness for the spell Entangle because it can be used creatively. The Druid in my long running Urban campaign has used the spell once... one time in 17 levels and 3+ years of real time play. The Druid used Entangle on
the water slicked vines and moss on a subterranean cliff, to catch her falling party mates after their rope was cut scaling the cliff.
Spells that can be used in that fashion get wide latitude from me.
As an aside did Entangle change from 3.0. I seem to remember a notation in the spell similar to the Web Spell that sustained fire negated the effect. We have always played it as thus, allowing say a Burning Sphere to carve a path through the area of effect.