I read an article about this a while ago, here is the authors comments, he brings up some good points about some serious problems.
some private opinions
The OICW, to be effective, relies upon computerized fire control module. Both KE and HE modules could be fired with iron sights, but this greatly reduces the overall effectivness of the system, so as soon as the batteries goes off, or the computer/optics/laser get any damage, you'd better throw the Fire Control module away... But it costs more than half of the whole system price, and that's some 5000 dollars (probably, much more), so guess what the soldier should do when the Fire Control module fails...
Another point is that 20mm programmable ammunition is no way the cheap round.
Third, the whole system is bulky and cost a small fortune...
Resume: In my opinion, the OICW is a weapon for so called "peace-keeping" operatrions - low intensivity conflicts, when US troops had always good supplies (of batteries and spare parts) and carry the weapons for limited time (forgot about weeks-long raids beyond enemy lines). It also costs too much, and now i'm doubtful about the plans to issue the OICW to every 4 soldiers in every Infantry squad of the US Army, USMC etc (the OICW is intended to replace M16/M203 combos and M249 SAWs, as well as some M16s or M4s).