Guys, guys...
Let's not make things any more complicated, intimidating and dramatic than they really are.
There are hundreds of skulls and spells in 4D. As someone already pointed out, you don't need all of them to get along very nicely in the game, (unless you aim to be a top PK, in which case the extra edge of some top skills might make the difference. Which is exactly why those top skílls shouldn't be too easy to acquire). In fact, you don't even need some of them at all, since there are substitutes and players have different strategies and preferences when playing. How many of the skills that players have do you think they actually use?
In a way I am glad this discussion about the Trainers came up, since that gives me a chance to bring up a very common misunderstanding - people who think that the 'harder' zones are filled with high-level aggressive mobs that you 'have to' kill.
With very few exceptions this is not so. The only exceptions I can think of offhand are the three so called Uber Zones, (Prehistoric Forest, Dark Planet and Dragon Caves) and possibly also Troll Forest. And if you find any trainers at all in those zones they will be for very high Tier skills.
The rest of the 'harder' zones are 'hard' more in the meaning that they may be a bit tricky to get through, and require some brain work. They usually have more of the undisplayed portals and containers, some of them have tricky mazes, they may have hints buried in the listen/smell or look behind/under/above descs, and they generally have more and harder quests. This makes them more interesting, and more challenging to explore. But you don't have to be a GM, or even tier 4 to get through them - with some normal precaution you can play them quite comfortably as a tier 1, level 50 player, There are actually very few high level aggros in 4D, and the ones that exist are mostly sentinel and can easily be avoided. Quest mobs are generally high level or have a regen script, because we don't really want them to be killed by all and sundry, Quest mobs are meant to be talked to and interacted with, not killed.
Quest heavy zones, like Fenizia, the Egypt-Kush-Punt zones, Enchanted Lands, the Aegean Islands, the Alpha Centauri Planets etc. hardly have any aggro mobs at all, and if they do, these can generally be avoided just by using a vehicle. There are also strategy commands, like consider, flee or retreat, you can set your wimpy high, and even if you do occasionally get killed by a mob - come on, how big a deal is that with automeld and recover at your disposal?
Having to kill a high level questmob to get the reward is really more of an exception than a rule. And even so, the main challenge in the Quest is usually to just find that particular mob. If in the end the mob turns out to be a bit too tough for you at your current level, you've still done the main work, and can easily go back and finish the quest when you've gotten a bit stronger.
As for the Gladiators, what is wrong with using a session getting to understand the skills and spells of a new Class, rather than trying fighting strategies? Each time you learn from the experience, and in the end you may have found out things that might make you want to try a certain Class. And once you have got an understanding of how the different Classes work, you may start winning the fights. And even if you lose a Gladiator fight, what does it matter? It doesn't even harm the Gladiator, they cannot lose exp.
The reason we still left the Gladiators open, is mostly to give all players a chance to test the different Classes. So use them as much as you can while they are still open, because it won't last for ever.
And the reason why people stay at Recall or stop remorting instead of exploring and Questing is not that they need to be afraid to get killed, it's just because they are lazy.