I see no problem with having both systems, as far as I see it, if we can have that, there should be no reason to debate the issue except for players who can't accept the fact that the game has options they don't want to use, or players who don't like either approach and feel they need a third option. Really, it seems to me that the whole issue only needs to be debated because in Oblivion, players weren't given a choice, i was either use the map for fast travel, or go everywhere in real time, and some players will say "If you don't like it, don't use it." And I'd imagine that's exactly what those who don't want to use any form of fast travel at all do. The problem is when players want some means to avoid going everywhere in real time, but don't like Oblivion's approach to it, and that should be fixed by an alternative. Though if such an alternative exists, there should be some sort of disadvantage to using map based fast travel, like say, the risk of random encounters with enemies around the way, it makes sense, because you could have that when traveling in real time, and if we're meant to accept that Oblivion's fast travel is just normal travel, except the game skips over it, than logically, there would be a risk of being attacked during such travel to, one would think. Besides, if the alternative costs gold and can only be used to travel to certain locations, there needs to be some sort of benefit to make up for this.
If I can only choose one, though, I'd go with Oblivion's system, because it's most convenient, simple as that, and convenience is the entire point of fast travel. Morrowind's version of fast travel got extremely annoying after I had to go to the nearest silt strider, take it to a different town with a silt strider, then take that towns silt strider to a town that has both a silt strider and boat (Because for some reason Bethesda thought it would be a good idea to have travel NPCs have only at most four destinations they can go to even when there are actually many more with the same kind of travel service.) then take the boat to another town, and then walk out town a widing path through the mountains into he wilderness because Bethesda thought it would be a good idea not to have any travel services in thw town I actually want to go to, and all this as part of some boring task to deliver some silly message that the quest giver was too lazy to deliver himself, and then had to repeat the proccess several times. Sure, you can say that's "realistic", but I don't play games for realism. Now, realism is nice as long as it doesn't come at the expense of gameplay, but when the "realism" people obssess over starts to turn the game that's supposed to be fun into a chore, then it's going too far. Of course you're free to disagree, but those are, at least, my thoughts on the matter.