That's where I'm at. Money's not a huge concern . . . so I'm thinking the peace of mind of just swapping it out is worth it along with the potential avoidance of a disaster. My wife's sister just went through that. Found out her water heater was leaking and flooding the basement the night before she left for vacation. She walked into the basement and took a few steps on squishy carpet. Looked at her teenage son--who lives in the basement--and said "OMG, the carpet is really wet!". He said "yeah . . . it's been like that for a few days." SMH. That's a whole different story.
Not sure why this didn't occur to me before--sometimes I'm a little slow. We have the wood subfloor in the basement. Looking at where the connection is made for the sprinkler line through an acces panel in the ceiling, it looks like a line could come off the main water line and then just get run under the subfloor and back up in the furnace/heater room and tie into the sprinkler line to put it on it's own, separate line before a softener. Probably above my plumbing ability, but I bet it's easily done by someone who knows what they are doing (probably with Pex). I'll have to get my thoughts together on that one.