Reducing ezreal early Q cd accomplishes nothing for this one reason

No one in their right mind will even spam Q at the 6.5 second live CD. let alone 4.5 or 5.5. Why? you will go oom. the only time you ever use Q if there are minions out of range and you want to farm safely without getting poked. which means you use it every once in a while Before you get the tear. thats not what ezreal needs

to sum it up. ezreal has an ability that is worthless. his W, I'd trade his W for 3 cannon minions every game if I had the choice. and a passive that does not fit his playstyle. first off hes not a hyper carry neither does he auto near as much as other ad carries to have his AS increase. so its really a strong passive. on a champion that does not care that much about it. Ezrael basic attacks do about as much damage as a 3 item adc at late game. his damage comes from Q triforce procs. in which. doesn't scale that well because it scales off base ad. and the only way to increase it is with steraks gage. which doesn't really work on him for obvious reasons.

either make him a true caster. reduce his old ult CD or make it deal more damage. and make his W useful by adding an ad ratio. or somehow buff his aa damage (idk. a new passive that empowers his auto attacks after using an ability. or whatever. increase base ad depending on stacks etc).

the only time ezreal is meta is when ad carries are weak and so you pick him because hes not going to feed his ass off. rather than hes going to carry you. because he can't really dps tanks or bruisers well. and if he can't land his Q his damage is ignorable even by squishies.