*KA101 launches Analytical Fire Wall O' Text.*
Skills generally: something like Code Breaking could be a valid *overt* skill, whether military ("Hudson. Run a bypass.") police (if the door alarm goes off, they'll execute the hostages) or piratical (opening the safe you stole *without* risk of breaking the fragile PreZero crystal discs it's supposed to contain). If skills must be locked together, consider letting one group pinch-hit, at reduced effectiveness, for another skill's domain.
GH1 example: currently, no matter how much Knowledge, Science, and Investigation I have, I just can't understand PreZero languages I find on a monolith (because I don't have Mysticism). BUT I *can* crack PreZero data-storage devices (the Genome and Ziggurat computer come to mind), presumably coded & written in PreZero languages, and understand their contents just fine.
Thanks for the comments. One thing about the skills is that ever since they've been decoupled from specific stats, there's no reason why a single skill can't do multiple things- just paired with different stats.
Even if the skill system isn't changed, I think that converting MechaEng to a talent + having multiple Renown scores would be a good idea.
Re skill+stat: PLEASE make the connections explicit. Example: conversing at the party, lines, skill/stat involved, and any significant effects, in that order:
"It's VERY nice to meet you!" (Conversation + Charm) (Flirt)
"So, have you ever used a Reflex System?" (Mech Piloting + Charm)
"I am the invincible $PLAYER_NAME!" (Taunt + Ego) (Passionate)
"Don't you feel a connection between us?" (Mysticism + Ego) (Spiritual) [and/or?] (Flirt)
Re MechEng: Strongly oppose. If you do make it a trait--something that costs 5K XP to buy and only 5 total slots through the entire character, IIRC--would you kindly let players have better stock mechs? The idea that "all non-quest-reward mechs should have some flaw which needs MechEng to fix" makes having access to MechEng kinda important.
Re multi-renown: Support. Performance != Piloting, which need not equal SF0 combat skill. Possibly detective or med/sci skill (if the PC helps knock back a few epidemics, that should attract attention).
Generally: I think Crucifix is onto something. If xe's correct about 100ish Renown giving GH2 opposition pilots Mech Piloting 21...well...that explains a LOT.