I have two questions here.

1. What's you're opinion of this?   http://www.defensereview.com/the-big-m4-myth-fouling-caused-by-the-direct-impingement-gas-system-makes-the-m4-unreliable/
and
2. Does anyone think I'd benefit from the H3 buffer/heavy buffer spring/extractor spring mod on a 16" middy shooting primarily 55gr.? Or would it be too heavy to strip new rounds off reliably?

I'd say try it if you're curious.

Are you suffering any reliability issues right now? If not I'd say experiment if you want to, but don't expect it to be a drop in miracle worker. I've run a 9mm buffer in my 16" carbine and I really liked how well it worked. It didn't improve reliability (my rifle has been 100% reliable in the 700+ rounds I've put through it so far) but I did notice how the recoil was affected, and I think it slowed the carrier and improved the felt recoil, but I don't think it's needed at all for "reliability's sake".

If you're gun is running good, keep it that way unless you like experimenting. The heavier buffer is a way to increase dwell time in carbine length systems. The midlength gas system is another way to increase dwell time. Seems like while they may no be mutually exclusive, there's not much point to run them together.

I say if you're curious and want to experiment, go for it.

If what you have runs fine and you don't want to spend extra $$, don't mess with it.

Some rifles wont even function correctly if you try heavier buffers. Just depends on the upper, ie had a 10.5 lmt that wouldn't strip another round out of the mag until i went to a car weight buffer and then things ran fine.  As the gas port eroded i was able to swap out buffers for a heavier one.

I can't think of any reason ata ll to run an H3 in a middy.

If you would like to experiment with it and don't mind getting extra weight buffers, try it, also try it on some underpowered ammo load to see if it will still work.

My new Colt 6721 carbine came with H buffer as standard equipment from the factory and it works well with my surplus NATO and 55gr Winchester white box (Q3131) ammo, I also have a H2 and 9mm buffer from my 9mm carbine that I will try later on with my ammo loads.

I'm running my carbine with M16 auto BCG with BCM extractor upgrade kit and mainly using PMAGs.

Ultimately my goal is to use the buffer weight that will work with all my ammo, even with some underpowered loads and ejects my brass between 3 and 4 o'clock direction.

I've never had much luck with anything above an "H" buffer. I've tried H2's and 3's...and honestly my guns tend to work less with them.

All of my AR's over the last 3-4 years have been run with exclusively with FA BCG's and 9mm buffers including my most recent 11.5" SBR build and I have yet to run into even one issue. If you did run into a build that short strokes when using a heavy buffer then my guess would be that the gas port on that barrel is too small.

Heavy buffers offer a number of benefits including more positive feeding, longer lock times, slower cycling which leads to better ejection and lower felt recoil. I personally wouldn't waste money on an H3 buffer when you can get a Colt 9mm buffer for less money.

I don't think it will make much of a difference in semi.

I recently put a H2 buffer in my 14.5" carbine to try out and did not notice much difference between the standard carbine buffer and the H2.  Reliability was 100% with both however the H2 buffer seemed to group the brass in a little tighter pile and was just ever so slightly less muzzle jump with it also.  I would like to try an H3 if the opportunity ever presents itself.

I've got an H3 buffer in my 16" Carbine.  It did reduce the recoil somewhat.  Didn't impact functionality at all, still reliable as it ever was.  I have a few thousand rounds through this rifle, never had a problem with the buffer system (now my trigger is a different story, but that was my own darn fault...)

In theory, do you think an h- buffer with heavy springs, extractor kit and an m16 bcg would run smoothly w/o hiccup? Anybody tried this with a middy?

what he said

I have 3 midlengths right now, two have H buffers and one has the ST-T2 buffer, they all work perfectly.

Depending on your weapon and the ammunition you shoot, your mileage may vary.