*sound of six-year-olds snickering*
An 8 HD, medium-sized incorporeal undead: nothing too crazy there. Ability scores are quite nice, with +8 dexterity, +4 intelligence, and +10 charisma. -2 wisdom sucks but is manageable. A 50 ft. fly speed isn't half bad, especially when you don't have to move around most obstacles. The remainder of the chassis is fairly standard, with only the 1d12 bite (with 19-20 crit range and 3x modifier) really standing out.
The real interesting bits are a bhut's many special qualities. Firstly, there's Dreadful Appearance, which causes strength damage to anyone who sees you for the first time. It's not 'friendly' in the strict sense, but given that someone gets lifelong immunity after exposure, that's unlikely to matter in practice.
A bhut's bite also delivers poison, which deals a non-insignificant amount of wisdom damage (2d6 initial, 2d6 secondary), and kills those reduced to 0 wisdom. Victims then get turned into new bhuts (who aren't under your control). Neat, and worth using against frail wisdom-based casters or something. Bhuts have a weird weakness to stone and earth, and take damage while passing through it. They're also very vulnerable to stone weaponry, which even bypass their incorporeal miss chance.
Finally, there's their main ability: Corpsetheft. This allows a bhut to possess humanoid corpses and turn them into zombies. I'm not sure I'd call it useful: it requires giving up on incorporeality, dreadful appearance, and your considerable dexterity score, but it does have the neat side benefit of nullifying earth weakness, and is less likely to have townsfolk attack you than your default monstrous ghost-self. It's also reasonably useful during infiltration or intrigue missions, I suppose.
I'm torn on what to rate this. On the one hand, being incorporeal is quite good, but on the other hand the bhut doesn't have much else going for it. Corpsetheft is niche at best, the bite attack is useful but underwhelming as a primary attack mode, and earth vulnerability worsens incorporeality by a fair bit (what's the last time you were not adventuring anywhere near earth or stone?). It's also tricky to find a class that fits this, which leads me to conclude that a bhut's relative power will go down even more over time.
-0 LA for now, open to suggestions for +0. Also note that this would still be playable, especially around mid-levels, it just wouldn't necessarily be good.