Two parts here, thought I'd simply make it into one post/topic instead of making multiple mosts within moments of each other.

First, differnt eras
What I mean here, is to have ships/stations from differnt eras, perhaps in some sort of upgrade type of campaign or something.  A couple mods i thought were interesting (Although I had massive problems in getting them to work) were ones that had vessels and stations from the 2md Century (Enterprise Era) to the 23rd Century (TOS Era) and Beyond (24th Century and such).  I am uncertain how (If at all) this could be done though, either simply just having them as part of a tech system, or using them for hull types (Scouts, Explorers etc...) and new classes replacing them as 'time' goes on (or research).

Second, Increasing limitations...didn't know what else to call it.  Perhaps caps is a better word.
What I mean is, in Armada I, you had an officer 'cap' that could be increased when you upgraded your starbases.  Perhaps an option at least, where one can do that if they so wish.  I noticed there seemed to be some sort of line in the original bases in Armada II to allow for this, but it never works? Not sure...

I think that about sums it up, I hope I made sense here.

Weaker and older ships that can be built in greater numbers than new one would be better.

Yep the idea of different eras has been mentioned in the one and the other Fleet Operations meeting, but at the moments there are no plans for such a feature. oldies from the past might appear in future versions within other features

Such homeworld-like build limits would technologically be possible and will probably be features by one of the new races after v3 as a racial feature, but the current races will stay in their basic gameplay like they are. Balancing has been adjusted in order to fix some issues. Nearly all balancing mechanics are complete reevaluated in the v3 release.

i know you can upgrade odf easily enough but you want to replace textures as well to make it in to a different ship?