Comment by l0b0

What seems to work for me is specifying exactly which part of the solution you might want to replace and why, phrasing it like a brainstorm idea rather than a fully thought-out proposal: "Would it be easier to frobnicate if we replaced the blarter with sshd?" This should make it clear that a) you're not suggesting that the blarter feature set overlaps exactly with sshd, which would be an astronomical coincidence, and b) you're focusing on frobnication to the exclusion of every other axis along which you might measure the usefulness of the blarter.

In my experience the responses are always productive - most of the time they are happy to explain why the blarter is better at frobnicating or why some other useful feature of the blarter trumps sshd. And once we have a dialogue it's easier to introduce other brainstorm-y ideas. Conversely, in the rare case where they realize that sshd is actually a good alternative they simply hadn't considered they often instantly volunteer three other reasons why it's more useful than the blarter.