Most people (in the US since the word flan is used differently in countries like the UK) when you say flan think of the Spanish/Latin American dessert and many react with "I hate flan" since it's been marketed to the point where even Jello sells the stuff. But I don't find a negative reaction to "creme caramel" even though they're the same thing with a different name because it hasn't been marketed as creme caramel.
What you describe above is a baked custard, which flan is, but specifically a caramel-topped custard.
Flan really isn't particularly heavy, though. It's the lightest of the big three baked custards, in terms of richness. It's composed of mainly whole eggs and milk, versus the richer pots de creme and creme brûlée, which have more yolks and use cream. The use of whole eggs makes it firmer and more eggy-tasting than the others, but it still shouldn't be unpleasantly firm.
Basically custards are a tree with various branches, creme anglaise being the root. Changes in number of eggs, use of whole versus yolks, and liquid used distinguishes them.
As for overbaked, aside from curdling and splitting which happens, tiny bubbles along the sides of the custard are an indicator and I see tons of flan with those bubbles along the side. Overbaked flan is unpleasantly eggy since the eggs get that sulfurous flavor.
Anyway, I wasn't intending to be argumentative or whatever, just teasing because I'm afraid of ever suggesting flan the reaction to it is so negative sometimes. I was trying to be sneaky!