IDK ... I get that datacrons suck, and if you want to be competitive in PvP game modes, you're kind of forced to go for them.
But so far I haven't spent any money on datacrons. Sure I spent some in game resources - shard shop currency, ally points and also crystals - but nothing that I wouldn't have spent on other things anyway. I have a lvl 9, a lvl 8 and a lvl 6 as my best ones so far. And it didn't cost my anything other than a slight shift in resource focusing.
On the guild side of things, we've had 3 people leave our guild due to datacrons - but so far it has been players who were already kind of burned out on the game, and had considered quitting anyway. But if I remember correctly we actually had more people leave when they revamped Conquest into it newer more grindy form.
So IDK ... I hate datacrons as much as the next guy, but I don't think they will break the game much more than Relics or the Conquest revamp have done.