Yera: I think it simply is a good way to enforce good behaviour. The ability to pack in a ton of ware in chargen... without paying the extra BP costs to keep your resonance is worth a lot to a min/maxer.
a)Technomancer is a poor choice for a min/maxer, adept hacker probably is a lot more powerful. b) Latent techno is even worse. You pay 5 BP at CharGen for nothing, if and when you emerge you still can do nothing with your technomancer status. You will have a huge karmasink to bcome the OMG L33T <y83R H4XX0RIf the player is well behaved and roleplaying well as opposed to simply powergaming for everything he's worth. Then the GM can be benevelont. If not, well you can use 'wish wording' to twist the players choices into a black hole he may never escape. If it's in between... you might simply do things like pick an unoptimal stream (like say a "networker" on someone who used charisma as a dump stat).
All the latent qualities do not work for power gamers, so any GM should be in the clear.Random would be fair, or at least screwing everyone equally, but letting the player decide which stream to get and if he wants a paragon, will make everyone happy without making the character overpowered.