It doesn't work for a myriad of reasons. There has to be some stakes in this world invasion (I'm going to come down and kill this planet). Not only does Ronan undercut Thanos (which is supposed to be super baddy), but Ronan is then further trivialised being killed by a thrusting pelvis. It's not compelling at all and rings very hollow. What was the point of even spending any time building up this half baked villain with a generic plan if you were going to write him away is such a stupid manner? No stakes takes away any sense of urgency or me caring about any of the characters.
And if we're to pull away from just GOTG and look at the MCU, they've struggled mightily to create compelling villains, and GOTG was there "well screw it, we're terrible at this, thrusting pelvis death it is and people will love it"
For me personally, it was very offputting... GOTG 2 has an infinitely better climax and ending.