In theory, this isn't wishlisting. However, the both sets of Guard rumors seem to have a lot of wishlisting built in...
Stormtroopers as Troops? Try Veterans in Carapace. Cheaper and better armed. Or Sisters of Battle. 8o
There are things Guard simply shouldn't be able to do well. If Guard can have halfway decent Psykers, that changes the army design. Let Guard suck at Psykers.
Penal Legions should be Troops. Like Cultists. Last Chancers should be a special Troops entry. Actually, tho, they're better represented as Veterans.
Rough riders are fine. I not only use the older Tallarn riders to match the mass of Tallarn infantry in my Guard army but they also ride Dark Elf Cold One raptor lizards. I suppose you could try the Lizardmen Komodo-style Cold Ones as an alternative.