This idea needs more work on mechanics, but is not a bad idea at all and worth exploration.
The two biggest things OHM should focus on are liquidity and being a currency. Sushiswap solves both.
However, I am against this being a merger. Maybe acquire a major stake and let Sushiswap still function independently. It may be cheaper to acquire than to launch an in-house solution. But either way, this is probably more important in the longer run than a lot of other proposals I've seen (personal opinion).
Clear benefits:
1. Hundreds of pairs can be launched across every chain in OHM or gOHM. In case we all forget, this is a core goal for OHM.
2. OHM not only facilitates the Ownership of liquidity, it also becomes the biggest player in rental liquidity. This is the second core goal of OHM. Liquidity > price.
Everything else is noise. To be a major player in DeFi - you need a big market where its traded.