The "if everything is OP everything is balanced" style is what keeps me playing FfH. If you're going to change the event, either make it rarer or buff the other option. Don't nerf the fun part of it.
Attach another event to keeping the orb for study, where your sages determine it's properties. You could choose that it radiates magic power, and it provides a random mana. Choose that it exudes an aura of peace and wisdom and it gives Disciple units built in the city +2 exp. Say it strengthens metals held near it and melee units built there have a chance to get +1 str. Say your sages found nothing, but the whole city seems better with the orb in place, and it provides a :happy: benefit and a few city-buffing effects.
Anyway, back to the actual topic.

If you intend to play Hyborem on an Erebus map, start with the Lanun. Erebus's smart civilization positioning will give you a nice coastal start. Get fishing, start teching. By the time you have to start settling the less appealing inland areas you're ready to switch.
The trick here isn't that Lanun on the coast tech well, although that is a good thing. It's that you switch when they've about reached their potential. Inland cities aren't nearly as good for them. Their Boarding Parties are weaker. The same mapscript that gives them such a nice start also generally places them such that they can't expand a lot without going through someone else.
I always find as Hyborem that my greatest threat is my former civ. It's been set up intelligently by a human, and now is enjoying all the bonuses the computer gets to make up for being dumb. If you start with the Lanun you're a lot less likely to finish up your neighbors, emerge onto the world stage, and realize your former nation controls half the world.

Plus the coastal start gives AV a better chance to spread around.