Well since it seems this thread has been revived, Ill guess I'll state what I've stated before.
IPC's are a in a good position when it comes to roleplay and feeling different from, say, a human. I'd argue that more people play IPC because it actually feels alien, not because it is strong. But, that is just conjecture, really. When it comes down to it, IPC's only have three issues.
In sec/command roles, a IPC is easy pickings, and is seen as a loot pinata for obvious reasons. For this reason, any IPC's in this role that don't partner with other species will likely be killed without any fighting chance against a enemy with a EMP. Sticking close with other sec/crew members does help remedy this a bit, but still, it is a liability to be in a combat role as a IPC. I personally see this part of the races mechanics, and that its not meant to be played in combat roles without support, but that's just me.
IPC's that are targets to enemy agents are very easy to kill, as long as they can find you. There is little you can do to defend yourself, if anything, assuming they use a EMP. Even if they didn't, the brute weakness will still put you at a considerable disadvantage. Its pretty much a free objective if you can isolate them.
Finally, the EMP range (in this case I am talking about agents 2 tc nades they get) tend to be so large that killing an civi IPC, unrelated to the engagement, is quite common. An agent could use a nade to keep themselves from being tazed in a sec chase, and if a IPC happened to be in that area, they would be instantly killed.
With the last point I made, there was a PR a while back to fix it. It was meant to make the IPC's take heavy damage from a EMP, and be stunned for a decent while (half a min iirc) instead of instant death. That would of solved the issue of unwanted collateral deaths, while still making sure they are easy to kill if they are your target or your pursuer (sec). Sadly, it was shot down on the basis of being a buff to IPC, but really it was anything but. I can't speak for others, but if I knew I wouldn't kill some random IPC in the hallway I didn't see every time I prime a EMP nade, I would use it far more often.