It's more complicated than just pure strength. Although that does have a lot to do with it.
If a women is able to meet the standards that the males go by (meaning they don't use the female PT score sheet) than I don't have an issue with them serving in a line platoon. They need to be able to carry the weight though. My platoon sergeant said that every man had to be able to carry our heaviest man (who was 6'4 and about 240-250, maybe even pushing 260 pounds) while in full battle rattle (you and him) at least half a mile to make sure that no matter what happened we could get everyone out dead or alive.
Of course not all units will demand this, but it's important to be able to do tasks like that.
Another thing that will have to be addressed is personal space. The military likes to keep men and women separated in terms of sleeping and bathrooms (for obvious reasons), but that could create issues. At one point during a deployment we had two female radio operators tasked to our outpost for some reason that I don't know. My platoon was all sharing some very tight living areas, and we shared two bathrooms (outhouses). When the two females were sent to our very tiny outpost, we had to give up where we slept and one of our bathrooms. So two females got a sleeping area too big for themselves and a shitter, while we had guys try to find a place to sleep. We had two small bunkers for rocket attacks that fit about 12 guys between the two of them, a few guys slept in humvees, and the rest of us slept on the dirt and hoped there wasn't a rocket attack that night. Needless to say it was very annoying. Issues like this will have to be addressed. The two females with us happened to leave about 3 weeks later, after our outpost was attacked a few times, and they didn't like being that far out in the shit.
But I'm sure the military will do it. I'm all for it though, if they can do the task right, then I don't worry about it. I've seen a woman MP who was unable to kick in a door, and I've seen some that were. I've seen a woman driver speed up and hit a VBIED that cut off her convoy, and then pick up her M16 and shoot the driver of the vehicle dead while he spun off the road before he had a chance to blow up, and I've seen an Infantryman who was tatted up and really buff curl up into a ball and cry when we took some pop shots on a vehicle patrol. So gender (to me) doesn't matter for combat. It's all about your abilities.
I heard that they're not going to open up every single job, so units like Rangers, Special Forces, SEALS, PJ's etc probably will remain closed as they are elite units that require much more. Maybe even Infantry and Scouts. But some jobs that are closed to females (Artillery, Tankers, 160th SOAR pilots) should open up and that'll be fine. They need to be able to meet the standards that males have to meet though.
Complex issue though that's for sure. But I'm all for it if it's done right. I trust the military will do it right. Much like gays serving, I don't care who you are as long as you wear the American flag (or Canadian or the UK, or Australia, all great guys and I had the pleasure of serving with) on your shoulder and are able to do your job.