(It feels a little awkward to post about gameplay now that I'm sorta official, but please don't let that affect your thoughts or posts)
Rather than make the suggestion outright, I'll put up some questions and hope those with more experience can answer:
1. Did projectile spores help noticeably against marine turtling in NS1?
Armouries didn't repair armour and aliens could get Focus, but welders were cheap...
2. Would projectile spores detract too much from the desired Lerk v2 behaviour of needing to get up close to fight, like the other aliens?
Assume it'd be considerably weaker than sporetrail since it's safer to use.
3. Should the Lerk need to get up close to fight?
4. Were projectile spores too easy (/boring) to use?
There have been ideas for new takes, like adding the Lerk's momentum to the emitted sporetrail, which could let you cover much of the marine base by doing a high-speed U-turn at the entrance, while still giving the marines some chance to react.