I am still relatively new to this game, however here are my thoughts on your question. At first, I too,thought it was a bit of a waste how I have 200 blue prints for a mech I don't intend to use. However, while some BPs, I would agree are less desirable than others depending on your play style. On occasion, an event may feature a task; "Rank up or upgrade 3 mechs and/or weapons" for example. It is likely that you have multiple low level mechs or weapons in which you've collected a number of blue prints for. These "useless" blue prints can be used to accomplish these tasks without spending a fortune.
So while yes, I for one am much more enthused when I receive a blue print for a Missile Rack 8, as opposed to an rpg 4 at my current level. The build up of low level weapon blue prints have enabled me to consistently complete events in a cheap and efficient manner.
I don't however have any info on clans, but that would certainly be awesome down the line. Judging by Plarium's other titles, I would imagine this is a feature they're considering, assuming they find this to be a feature that would add to the game in a positive manner. I imagine its highly likely, in time, in some form, clans will be present ;)