Sure, I mean that Maker changes in monetary policy will directly impact Aave DAI borrowing rates (right now they have indirect, market impact). Aave handing Maker the keys to the DAI borrow rate also hands it the responsibility that come with it, and one should be mindful of how differently Aave rate changes ‘imposed by Maker’ could be perceived.
To expand a little on target rate spread, what I find strange is that suppose you match 0% spread with ETH-A borrowing (taking into account the Aave ETH-A lending APY, lending rewards, and borrow rewards). Your net borrow rates for people who supplied something other than WETH to Aave will be downstream of that. And for collateral types that are also available at Maker, DAI borrowing may be cheaper and/or more expensive. I’m really not clear on why singling out ETH-A just because it is the ‘flagship offering’ makes sense.