Well, it might just be me, but I think there are some players who would prefer to play/level till GM in just a few zones, and then spend the time after GMing questing and or exploring. While I was like that too (I spent my last two class remorts levelling up on dock workers and lunatics), I'm not sure how other players would think.
There will be players who give up half way due to the 'grinding' of the same mobs for xp, or those that manage to GM, but then lose interest because they don't know how to quest effectively. Or just reach GM, haven't seen the many zones that 4D has to offer and then leave.
I would think that this is the reason why the new system was implemented.
I do see your point Iwku, in that giving hints may lead to quite a lot of frustration to players whilst they figure it out in the map room. I'm also currently trying to find some trainers for my esper, and having a difficult time with some T3 spells, even though I'm a GM.
But, I'm thinking that as games go, there should be some 'element' of difficulty, and that difficulty shouldn't be restricted to 'level of player + eq versus level of mob'. Whether that difficulty should also include skill/spell hunting is the issue here, and at the current moment, I'd go for the hints at tier 4. For Tier 4 skills are somewhat "uber", so I'd say have hints, for these hints would narrow it down to maybe 1-2 zones.
Maybe other people that are levelling currently could give their opinions here, so that it'd be better for the imms to decide on how the directions to trainers should be presented.
*On second thought and might not even be related, how about something like a journal that updates itself each time you find a trainer or do something else? I'm thinking of something along the lines of the might and magic journals (at least, for MM6, MM7, MM8). It could update itself each time you type 'practice skills/practice spells' at a journal. So if you found Professor Botta, it would read Professor Botta teaches locate object or something. Useful if you find a mob that teaches a skill/spell you can't learn yet, since I noticed many T4 skills/spells trainers are with zones that have lower tier trainers too.
Journals could also extend to entering zones, or solving quests etc...