Same here, don't really see the need to have two options with the current set of rules. Can't now quickly think of any other army that has the same unit in special and rare. So for simplicitys' sake I'll go for "no". If there would be two stegadons I think they should have a clear distinctions between the two in the rules/stats as well as the points. If they are too similar to one another then I think it's better to have just one entry with different howdah options. BR Agrem
Stegs in Special could be a way of getting a wierd kind of monstroues cav. They would need to be changed a bit, and would of course need to be degraded from monsters, but it would make for a unique unit.
Current proposal is a 155pts S5 stegadon with no multiple wound impact hits and the only upgrade being the blowpipes (it comes with giant bow). It do, however, have Scaly Skin 3+. At that price I think it's a fair deal and allows for a cheap impact hit monster. The rare version is 190pts with more options. The Engine of Gods is also being tweaked.
I like it. It is still potent but affordable enough that it isn't a killing blow to your army if a cannon takes it out.