It was a huge fight over nothing.

It was a huge (and successful) resistance for nothing, I'd say.

With SegWit2X activated, we probably wouldn't have had such congestion issues on the blockchain. Probably the average transaction fees for sending bitcoins would still have been a bit too high for coffee-sized-transactions, but it's a great difference between "high" and "insanely high". Probably there would have been sufficient idle capacity that "stuck transactions" wouldn't have been a problem. There would have been enough on-chain capacity to allow for lightning channels to be established and closed. And the roadmap would still be the same, with Lightning hailed as the scaling solution. Bitcoin would probably have remained strong, dominating the total crypto market cap (today it's below 40%). Had SegWit2X become reality, Bitcoin Cash would have gained much less traction.

Flipsides? I see two:

• The Bitcoin Core developers would have lost some power; a precedence would be created where the few persons with commit access to the github core repo would no longer have veto power over changes. I do tend to consider this as being a good thing, though the most important Bitcoin Core developers may disagree with me.
• The "slippery slope"-effect, what to do when we're banging our head against the 2 MB block size ceiling again? The obvious answer is to increase the block size limit again, but I do tend to agree with the folks saying that gigabyte-sized blocks are dangerous.