Personally I only abyssea leech jobs for which I have most of the skills levelled already. If you leech a job for which you have no skills, you are going to spend more time skilling up than you saved leeching.
If you'd just rather play a more active role while leveling, that's a perfectly legitimate choice. But rationalizing that you're saving time by having to do less skilling up just isn't true.
doesn't take that long to skill up most skills. Pick a skill level appropriate crab and swing away (Kuftal > Boyahda > Abyssea is the basics). Skills come easy, and once you're at Abyssea level skill it's even more mindless with Abyssea and regen/triple attack atmas. Total time expenditure to leech/level more quickly and then skill up is not going to exceed the total time to level more slowly in GoV (and then still need to skill up, but a little less).
You also need to remember that for most jobs it's going to be impossible to keep up all your skills while leveling anyway, so you're going to have to suck it up and go out specifically for skillups regardless.
Think of a WAR - there's no way you can keep even one weapon capped with the speed xp rolls in, much less multiple weapons.
RNG or COR? Even a fairly slow rate of party XP far outstrips your ability to keep up Marksmanship/Archery (and yes, those can be a real pain to skill up later but that's how it goes - at least you get level correction on your side at lv99 instead of having more misses against comparatively closer level mobs while you level).
PUP? No way you will be able to keep PUP's automaton skills anywhere near capped.
Even NIN, a job with one primary weapon and fast dual wield for skillups, is going to need extra skill. You can keep katana fairly close to cap, but you're still gonna need to level other weapon skills for procs if you don't already have them from other jobs (GK, dagger, sword, etc) and there's no way you'll come anywhere close to capping ninjutsu just through leveling.
Mages? Good luck keeping all your magic skills capped in FoV, that's simply not possible. It was hard enough to do at 75 in old style slow exp, and it's silly to expect any mage leveling in today's FFXI would be close to cap just from exping.