I think the consistent share feedback due to vardiff was the biggest attraction of miningpoolhub. Many people mine here exactly because of vardiff (was definitely a large part of why I chose this pool). Like watson2316 said above, it's seamless for a variety of rig hashrates from small single GPUs up to large nicehash rentals. It is annoying having small workers rarely submit shares but also annoying for large workers to spam shares, and vardiff fixes both ends.
Sorry about this.
I like vardiff feature too. As ethereum stratum protocol's vardiff is vulnerable to share validation at some cases, it may harm your earnings. I believe people liked vardiff + fair distribution and not just varidff.
In theory, there's no difference whether if you insert share frequently or not. (Just fluctuates more if diff value is higher)
This is why most ETH/ETC/EXP pools have static diff.
There's 20, 30, even 50 billion static diff pools out there. miningpoolhub uses 20 billion static diff which is one of the lowest.
Current difficulty value is not that efficient/inefficient for most rigs because nowadays no one uses eth-proxy things. Every 1-way to 6-way range rigs work well. Nicehash is compatible as well.
I'll continue think about other workaround or special vardiff port too.
Thanks.