Eh, it's more of a take-it-or-leave-it. If it's a really really good implementation, it would require doing things in a way that just doesn't work with a MMO setting.
Like the most obvious way to make it "fun" without it being just another "venture" like squadrons and retainers were, would be to take a page from the Chocobo racing mechanics and have a "separate" game space from which it's played and "broadcast" if you will. You don't get to play the actual players, you're more like the coach, calling specific plays from a playbook. Implementations more like that of FIFA/NHL/NBA games can not be done primarily because those are real-time games, and a real sports game takes a minimum of an hour to play. That is just too long for the 20-minutes tops we get with other content. Also MMO players are not that audience, and we don't want that kind of audience in a MMO game, because that creates the type of feature creep where the game client has code for something awesome and complex, but also is neglected by all but 100 people in the game after everyone tried it and got the trophy.
Some people believe that they are healers-only, thus without there being stakes to "doing nothing", healers end up becoming an extra DPS, and that is broken gameplay. That wiggle room should not exist, but it only exists because the gear stats-creep tends to mean 4 or 8 players need less healing, rather than the healer does more healing. Hence, the only solutions to making healing as intensive as tanking would require lowering the window for mistakes to be rectified, or be more reactive to circumstances, or nerfing gear to be pointless.
As pointed out in the -many- "to dps or not to dps" threads involving healers, healers do not have enough to do -always-. Even when content is new, that wiggle room exists, as it ages, players pick the most lazy and ineffective strategy (cast regen, do nothing else) because there is nothing else for that role to do, because the game makes no requirement to be reactive in anything but extreme/savage. It would be one thing if more content had "heal the idiot NPC" type of mechanics, it's another where "the DPS are taken out of the arena, and only the tank and healer can release them, simultaneously", and we just don't see mechanics that make the healer do anything but run away when targeted.
Like in a traditional RPG (eg pen and paper) your GM would adapt to idiotic and lazy gameplay. One way of making the Healer do more work is by attaching consequences to not paying attention. We see that with half dozen versions of Doom/Death. Some of the 24-player content is so busy that you can miss things, and I'd argue that the 24-player content is actually the best content in the game for healers, because it does not let you "do nothing", there is always going to be something that you can do because the mechanics often require paying attention to the field and other players. On the opposite side of this, most of the 8-player content has no balance once players have out-geared it, and it's a choreographed dance once you remember the how it goes. The 4-player content is a mixed bag, and as Yoshi-P stated, has no instant-death mechanics, so there is never any reason for a wipe other than people not paying attention.