A question about retargeting MegaWizard created items in device migration

I was thinking about it a bit more, if this was the best strategy. I think having a script that retargeted all the IP would be more painful, since it wouldn't allow users to use IP across multiple families at the same time(e.g. a device in Stratix IV that is in production, but the same files may be used for a Stratix V design that will be the new product). If users updated all the megawizard files for SV, they would now have two sets of files to maintain. Plus, if there were incompatibilities, a script wouldn't be able to handle it, and the user would have to make the modifications by hand. So then I thought, why have a target family at all in the megawizard. I imagine the reason is to make sure it is known what family it was generated for. Though it may be compatible with all families (say the altpll), there might some day be a new piece of IP that is different(like fractional PLLs in Stratix V, although the designs I've run still accept the old PLL). So I think Altera's approach is pretty good, unless anyone can think of something I'm missing?