I personally think the let's blame the epidural for every problem on the planet is a junk blanket opinion put out there in an attempt to scare women (for a multitude of reasons) not to seek pain relief (not saying anyone's done that here - just in general).
I've had two. Will definitely have one this go round too. I was still 100% mobile (walked, labored in shower, used birthing ball and squatting bars) and had absolutely no trouble pushing extremely effectively. I had no assistance delivering and no post partum problems. No other women I know has either. It's actually joked about - the massive discrepancies. Like urban myths actually. "OMG - this one lady I heard had an epidural and she couldn't walk for DAYS!!!" or "My sisters friend's boss had an epidural and she couldn't pee normally for the rest of her life!!!"
That's just not how they function.
If your epidural is administered properly by the anesthetist, and you're treated with care by labor support staff who know what they're doing, trouble's with epi efficacy and pushing are rare at best. They can be turned up or down at the drop of a hat and are very easily controlled if placed correctly. Mine merely took the edge off my pain. I still felt everything just fine. I was up within a half hours time (had to deliver placenta and nurse first) to pee all by myself.
As with anything involving prenatal care and the delivery of one's child, the best advice is always to choose experienced personnel, and really know how to advocate for yourself by being educated about all options and procedures. If I'd have been told that having an epidural meant I'd be flat on my back I'd have laughed hysterically, and then went on to deliver elsewhere. That's simply not how they're meant to be utilized and it's definitely one of the biggest reasons they fail - so why would I allow myself to be subjected to that??