Yeah, I'm switching to MML for the most part, but it's not as user friendly as HMP used to be. I miss HMP's mech selection interface within the program and the different ways to filter by bv/weight/tech etc.
Honestly, kickstart a new mech design software package and sell me files of record sheets, like HeroLab does with files for each game. Expecting people to do tons of complicated maths to build or modify a new unit is just not realistic in this day and age, and the inaccessibility will be a bigger barrier to new players than the nostalgiafest of reusing old cover art will be.
At minimum, a product that produces stock record sheets and will allow me to enter a pilot name and adjust the cost based on gunnery/piloting would be a good new player product.