aa777888 - as others point out, MAP limits are only a real issue when taking off and landing - are you doing that at varying alts and temps or just cruising through?
Most of my flights lately are cross country. Interestingly, those are the flights that have peaked my interest in having an MLI or FLI even though it's a piston single. The quick hops are, as you say, not an issue, just figure stuff out for takeoff and landing. But I find when I am trying to make time and run MCP the entire way I keep a critical eye on things. For me it's not unusual to see a OATs variation of 10-20 degrees during cruise on a cross country flight, and elevation changes of 3000 feet or so. It's not just flat, boring terrain around here, it's mountains and seashores and everything in between. Yeah, it's only a difference of an inch or so on the MP limit, but again, it's a want, not a need, and electronic engine instrumentation is less expensive than separate gauges so why not? Bruno liked the idea, obviously, and I know you are all fans of Bruno!
The throttle limit is pretty obvious because if you keep pulling the Nr goes down.
Now you are just being silly.