Then I would suspect that the Droid 4 would be child's play. You don't even have to crack the case to get to the battery with the Droid 4. The back is user-removable with a small tool (or a paper-clip) - and once you get in the battery is EXPOSED but has a cover on it that warns that it isn't user replaceable.
While I would have preferred a user replaceable battery and even the option to add an extended battery - this wasn't a deal breaker for me. I've had two Droids (1 and 2), my wife has a Droid 1 she has had since release day, we've had a number of Droids come through my office, and I've only had 1 device that needed the original battery replaced during that time. Likewise, I've had a number of iPods, Touches, and iPads and had similar results. Especially considering that this is a corporate phone with a guaranteed 2 year recycle period and corporate warranty coverage (on an account that has dozens of smart-phones subscribed) - it just wasn't that critical of an issue to me. I can see why it might be a bigger issue to an end-user purchasing their device directly, but even then, I'd be pretty comfortable with the risk versus benefits.
Beyond that, I think the Droid 4 has a locked boot-loader - so rooting might be difficult or "impossible". My review was oriented toward the casual corporate business user, though - I don't root my corporate phones because they're not actually MINE to risk bricking.
I've published a picture of the Droid 4 with the back cover removed to my Google+ account and to my twitter account ( @dcolbert ).
https://twitter.com/#!/dcolbert/status/175246194275135488/photo/1 
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