I will say depending on how it goes, the road to 70 bonus is more of a curse than it is a blessing. For a lot of people, it can be a very inaccurate representation of the pacing of leveling, whether people are fully aware or not. Now, this in itself I guess isn't much of an issue, but you still do miss a lot of what can and otherwise would keep you busy, be it side-story quests, doing FATEs in the open world, or just grinding by other means.
As someone with several capped characters I can at least say for someone who is motivated and with a lot of spare time on their hands; which isn't particularly rare given pandemic, but you can easily completely cap a character way within that time frame, even playing casually. Which I do think is a significant issue consider the sheer effort required to cap a character without the bonus.
I personally feel that players should be given an option whether they want the exp buff, but I believe it should additionally; either have a much shorter time-frame on how long this buff lasts for, and I mean something such as 8-12 hours in-game time. Or have it so that the buff is a lot more restrictive- e.g applies strictly to story quests.
I feel like this buff should be a means of providing a slight kickstart incentive into the game, rather than something that actually provides the means of completely capping out an entire character. It's absurd
