In 2000 points I'd have it as 4th generation, maybe thirds if you want super magic, but not 2nd, that said, I have 2 slaan and when I finish my 40k army i'll finish off my lizardmen which will include another slann, (6000 points) currently only 5000. Anyway, In 2000 points, he'll eath up over a quarter of your point which is ALOT of point to spend on one model and is a big case of 'all-your-eggs-in-one-basket' and is probabely not such a good idea, more saurus is the way, point for point, rank and file infantry dominates all with all that combat resolution. Like 2 or 3 ranks, standard, probably a few kills aswell and if your very lucky and kill heaps or your against chaos or something you should have outnumber too.