Sigma 50-150/2.8 HSM OS shows me what I'm missing...

I didn't even know this lens existed until a few weeks ago...I had bought my camera and most of my lenses in 2009 and 2010, before the lens came out.

Considering getting a full frame camera, I investigated what I would need. Now with the help of DxOMark (the data sight used by DPReview) it became obvious that full-frame cameras had a huge image resolution advantage over crop sensors. It would appear that the lenses can't handle the higher pixel density of the current APS-C cameras...even going back to my 18Mp 7D.

The purchase of a camera and lenses looks to be an over $6k purchase...and maybe as much as $10k. But none of the cameras have the combination of features I'm looking for. Only Canon has Magic Lantern. So I decided to wait another year or two.

Sidebar: the features I'd like are an EVF with focus peaking, false colors, zebras, and a waveform scope, at least 24Mp and preferably 36Mp, solid low light to 25.6k or 51.2k ISO, 4K video, 4:2:2 HDMI out (preferably 8-bit), and on sensor phase detection auto-focus. The lenses I would get are a 16-35, 24-70, 70-200, and ~100/2.8 macro. Preferably all with IS. F4 or F2.8 TBD. Tamron F2.8 series with VR seemed a good option. My Nikon primes would work on a Canon with adapter or natively on Nikon.

So I decided to wait. The Sigma 18-35/1.8 and 50-150/2.8 are large and heavy for APS-C only lenses but they come out at the top for resolution and image quality. My long zoom has been the Tokina 50-135/2.8. Not the quickest auto-focus and no IS but decent image quality. And a long list of Nikon primes with adapters (see my equipment list). These are reviews: Photozone, Lenstip, DxOMark .

The 50-150/2.8 OS was just discontinued and seemed to be out of stock for Canon. For Nikon it was $1000. Used ones were going for over $800 on eBay. Various online rumors had a new Sigma coming out.
So I called Sigma. No...no new versions are coming out. However, some regional dealers may still have some. I called...and found a new one on sale for $800. And bought it.

It arrived today. I don't have pictures to post yet...but it is very clear that it is the sharpest lens I have. I was a bit stunned. The IS also helps. It is unclear if a crop would beat my Canon 300/4 IS at the same distance. It is probably close.

Now I see the IQ I've been missing. The Sigma 18-35mm would be an obvious next step. However even these lenses, the highest resolution on a 7D according to DxOMark, are still short of most lenses on a full-frame sensor.

Am I heading in a direction I'll never be happy with? :S