The battlebriar: a giant plant monster with lots of interesting abilities that is completely crippled by its 25 RHD. Yes, it has some pretty good stats: no melee type is going to complain about 32 base strength. Yes, it's got interesting abilities: Thorn Field in particular is the kind of ability a lockdown fighter would've loved about twenty levels ago. But in the end, the battlebriar is a moderately powerful melee brute that's outsmarted by a wyvern, yet supposed to be capable of taking on CR 25 threats. Anything other than -0 LA would be ridiculous.
This time, WotC's love of making variant monsters with different amounts of HD at least made the battlebriar slightly more playable. Slightly, that is.
It's still got 12 RHD, its stats are nothing special (in fact, a regular ECL 4 ogre is at least as strong in every stat but constitution), and its two slam attacks aren't going to be doing much against the foes it'll be facing. Its special abilities are reduced to Improved Grab, Impale (actually a rather nice save-or-lose, but grappling-dependent), Trample, and Thorn Volley (a disappointing AoE that deals small amounts of piercing damage).
Like its greater cousin, the lesser battlebriar falls short of what a character of its ECL should be able to accomplish, and similarly deserves -0 LA.