I personally love standardbred draft crosses, they just beef up standardbreds, smooth out their wretched gait (for riding at least :P) and make em shiny <3
As for Friesian crosses, I don't even like most friesians - people don't see past the hair. They're huge and box shaped, everything about them is boxy, I like my horses round. Crossing them with anything just makes a more square version of whatever they bred it too, too long, too angular.
I simply don't see the facination behind behind breeding for color either, breed Strong Healthy horses - I'm so sick of getting calls at our rescue for 15 year old blind appaloosas, at least 1 a month. Or deaf splash paints. Breeders seriously need to start looking past the color and the hair and looking at the health and sanity of the horses they're breeding.
I'm a firm believer in only breeding within a horse's 'circle' crosses are fantastic, but breeding two completely different animals gives you far too far a range of conformation faults to try to ward off. Look at my pony, who's got the top jaw of a horse and the bottom jaw of a pony. What I mean by 'circle' is breeding them with horses in their ancestry or descended breeds, or even breeds that are similar in style.