The Crank Brothers M10 is a good one, it has all the hex wrenches plus a T25 Torx and screwdrivers all in a long form package. Good enough for the average person.

In the end I did build a custom one for a bicycle that had an array of Torx and zero 6mm but it was a more expensive tool set than anyone would want to buy and it has bits one could loose if you don't put them back in the magnetic holder (though in my couple years with the tool and loads of use I haven't lost any.

Multi tools are great but I don't really feel the need to modify. Certain tools like a chain tool or whatever are low use tools but if I do want to use them a separate tool is better. So in the end a Crank Bros M10 with whatever other tools I need separately is going to do me just fine or something with bits will also work well and there are tons of those that already exist from Topeak and Wolf Tooth and Lezyne and others. Yes If someone gave me the chance to design my own personal multi tool with no real limits, I would probably make an M10 with the hex wrenches made by PB-Swiss and a modern crosstip screwdriver (no Phillips because it is outdated and JIS is fine but the modern Crosstip is compatible with both and more precise) and titanium throughout the rest of the tool to cut down a little on weight. I really wouldn't change much as I think that one is pretty useful for what it is. No portable tool set is really going to be great because doing work on a bike on the road just isn't great.