I'd say SEGA will be sticking close to the Wii for two reasons:
1) Sonic. Sonic sells. He sells alot. But only on the Wii nowadays, why? Well, two reasons I think. He resonates well with the Nintendo 'core', the people who only bought Nintendo Games in the GameCube era (Sonic Heroes sold 1 million + on GC). But he's also the second most iconic figure in gaming, so the casuals who buy for brand are picking up anything with Sonic on too. Plus he's got appeal to the younger market, which Nintendo seem to have a stranglehold on.
2) Lack of talent. SEGA studio's really haven't put out a 'good' game in a long time (Okay Valkyria Chronicles but it wasn't ever gonna be a big seller). On the HD consoles if your games arn't good or don't have some sort of appeal then they're gonna struggle. Last year for PS360 SEGA put out Beijing, Viking of Asregard, Golden Axe, Condemned 2 and Sonic Unleashed. I find it incredible that 3 of those are going to be million sellers (Condemned 2 deserved it), but SEGA can't really compete with most other developers on the system now.
So yeah, SEGA will like the Wii. As mentioned earlier it is ideal for most of their franchises, and lots of Nintendo fans deep down like SEGA too. They won't drop PS360 support but arn't going to be putting more investiment in, if we're honest though, it's not really a great loss.
@Grampy, what would the chart look like if you combine PS360 sales? Just curious. To SEGA PS360 is clearly just one platform (Except for random PS3 exclusives :S), but with porting costs most of the PS360 games are just one developement cycle.
EDIT: Just seen Iron Man is another PS360 million seller for SEGA last year. They get away with selling some crap 0_o.
