It's not inevitable that they'll get more bonus points even if they win a relatively close contest. Hants got two more bonus points than Essex in their defeat last week. If the first innings scores are say, Somerset 295 and Middx 305 and Somerset win, they'll still finish below Middx.
Whilst I'd feel a certain amount of glee if Middx or Yorks went down I don't think it's good for cricket if the counties that lose the most players to the England teams end up in Division 2, so for purely cricketing reasons I hope it's Hants. They were the dullest and most attritional team in last year's Division 1 and only stayed up due to the harsh penalties meted out to Durham, then they strengthened their side by signing ridiculous numbers of overseas players via various loopholes. Their XI for the Championship match at The Oval in July contained just four England-qualified players with three South Africans, two Aussies, a Zimbabwean and a West Indian. None of these players are available for England selection, so even if they're scoring hundreds and taking stacks of wickets every week they're available to Hants for the whole season.