hmm, regarding perf, I guess linux-tools doesn't have to exactly match the kernel version if you have one from something close to same kernel version, maybe you could force install somehow? I'm not sure, someone who knows debian better might be able to help there.
I don't have it with me today, but tomorrow I'll get out my db410c (with fedora+lxde, so should at least be a similar setup), and see what I can see.
I will mention, that these sorts of things could depend heavily on the window mgr, etc. Not sure what setup you were using on the r-pi2? (x11+openbox? Or weston?)
re: glimagesink port to dragonboard, afaiu the linaro releases should be using glimagesink. There shouldn't be anything adreno specific about it (it's all just generic opengl APIs), although maybe in the r-pi2 case they had some customized version of glimagesink for zero copy (to avoid the texture upload)?
EDIT: btw, I guess you should be able to reproduce the same issue with videotestsrc plus some caps filter to force same resolution and yuv format? If so, that is probably the easiest way for me to reproduce.