You have a far better chance of your request being heard at Recently active topics in Photoshop Family about Photoshop Lightroom as this is a user to user forum.
Adobe is more likely to see your request on that forum.
Got it. Thanks.
Plenty of other requests there for this so +1'd mine to several there.
Crop to the bit with the horizon, make VC, straighten the VC and make a note of the angle readout, return to the master copy and cancel the crop, set the angle.
Under lens corrections Lightroom 5.7 (and 5.6) has a new feature to correct distortions such tilted horizons, it works quite well. If that is not good enough you can use the Manual tab also under Lens Corrections. Please see Lightroom Help | Upright automatic perspective correction | Lightroom 5, there is a good video tutorial by Julieanne Kost.
If you are using a Mac you can start the Crop tool, Select the "Angle" tool, do a Ctrl-Mousewheel or Ctrl-Mousewheel gesture on the Magic mouse and zoom the whole screen to the area you want, do the straightening and then Ctrl-mousewheel zoom back to full screen. It is quick and easy. There may be a system wide zoom command on Windows too.