Hybrids work in endgame PvP and to a lesser degree in endgame PvE.
In PvP, it is far better to pull from two resources than one - ESO has resource based combat. Being able to manage resources better by splitting the burden will set you head and shoulders above the competition, assuming you have the skill to back it up. However, it is better to draw your damage from one stat rather than two, as Ultimates and certain other abilities use your highest stats to calculate their damage. So hybridizing for PvP is more of delegating one resource to damage and the other to utility and defense.
In PvE, it depends on the role you wish to fulfill. Hybrids are most viable as tanks, since damage output is not as important as survival. Most endgame tanks have about equal amounts of Magicka and Stamina. For healing Magicka is your go to resource, but a few builds and Templars can focus on Stamina or split between the two. DPS is almost required you focus on once resource to maximize damage. If you do not mind sacrificing firepower for more utility, divide your stats to a degree. But splitting half and half is generally not the best idea (cannot say if it is a bad idea).
So being a competitive hybrid is a difficult thing to accomplish right now, but not impossible. Your stat distribution will likely not be 50-50, but you will dip into both pools equally.
It takes skill more than anything to make a hybrid build viable.
@Mhylton44142 You shouldn't worry too much about end-game content at level 8. You will have plenty of time to try out as many build types as you want while you max your level. Leveling up a lot of skills will never hurt you in the end either so just pick something that looks cool and try it out. Respecing in this game is very affordable too.
I play a few heros and the one I have the most fun playing is my Battlemage Sorc. He doesn't PvP though so I can't speak on that point yet. He split stat points 1:1:1, wears 3 heavy, 2 medium, and 2 light, and has never had a problem with any content so far (he's vr3). I've leveled nearly all of his skills so when the time comes to min/max I'll be able to do anything I want with him.