OK... I'll bite...
My Demands, although...I've always wanted to claim a 'Manifesto'...those were very 'IN' in the '70s...
1. Base Diplo horse being ...slower is only OK if there is another benefit. The 'freeness' is not a benefit. Any adult (and the devs are all adults... no matter if any wish to deny it ;P) knows time is not free. Of course, some in many MMORPGs have ruined economies because "it cost me nothing to gather the components so I can sell it for much less than that other crafter"...but I digress (wouldn't be one of my posts without that and parentheses)
2. Such benefits need not be unbalancing in even the slightest way. Often all you have to do is appeal to the vanity of the virtual toon and "stuff" (as George so eloquantly puts it) - Make there be a Diplo-HorseTrader that has the ability to 'swap' your horse for another color. Having the SAME color choices people who invest no effort in BUYING a horse has merely moves us out of 'very shafted' into 'slightly shafter 'cos we still expended more effort and spent more time' category. I'd hope something like mottled or rarer 'solid' colors were available. Perhaps, if you got the ghost and decided to make diplomats FEEL special (and warm-fuzzies) you could offer special Diplo-ONLY mounts along the lines of Hellhounds/Unicorns etc at the same or slightly LOWER ;P levels as 'regular' non-diplomats.
3. Another benefit is that our 'tack' (or is it tact ? ;0) could be 'special'...the problem is unfortunately that the basic tack is invisible. If it is not a bug and it is MEANT to be non-visible - then it is easy, make a simple 'blanket/cloth' horse tack visible on starter diplo horses but not 'regular' ones - you get the drift - it doesn't HAVE to be faster...
4. Create ASAP a quest or what have you to get your horse upgraded to 40 (and keep it in synch with bought horses if you up them again... or lower it if you lower them)
5. Work on the quests you already alluded to
These could add more speed than the standard horses, and/or other benefits that I haven't thought of, but the amazing creators of Vanguard have (no sarcasm - I WUB dis game ;P)
6. Let me know if the gnome Gloop who destroyed the Beta world was invented by Gebron or whether Gebron saw my best friend logging off 2 minutes before he finally used the name of the gnome with the doomsday Llama device and was inspired by my friend Gloop. (History: Gloop was born on Cazic-Thule, in '99, a Gnome Magician. He is slightly eviler now as a Necro since there is no other 'good' pet caster atm.)
7. I'd like the letter 'M' stricken from the English Language.