The shtick of Expendables franchise is that they resurrect older or fading action stars, placing them into this ultra-violent world of mercenaries, which is an homage to action films of the 80's. It's been successful for them, but apparently not as much as they think it could be.
Deadline reports Sly Stallone made statements at Cannes about changing the direction of the franchise, by getting a PG-13 rating. I'm sure there is a collective groan coming from their fanbase, as this is obviously a cash-grab. Instead of allowing the franchise to be exposed to the next generation of action genre audiences. I assume he means the generation that has made Fast And Furious one the biggest action franchises.
“We want to reach as many people as possible. It’s very close to an R, believe me, it’s right there. But I think we owe it to the next generation. We thought we’d join that club for a while.”
While I understand the business angle, trying to get more asses in seats and recouping the increased budget. It seems like a slap in the face to the fans who have supported the R-rated franchise. Another reason for this move might be to convince potential additions to the cast such as Jackie Chan. Even though, Stallone had made comments that this movie would outdo The Raid, it's starting to sound like this franchise might have the wind taken out of it with this move.