the reason the current 1-1-2 and solo jg setup is for a few reasons
top- you want a reliable solo laner usually tanky up top since it is isolated from dragon and early barons are rarely ever a problem to watch for so they are going to be alone 1v1 for the majority of the laning phase, hence why a lot of late game champs like nasus, trundle, jax and mundo end up there, and part of the reason riven gained so much attention as a lane bully
mid- mid lane is usually high burst and has shifted more toward high mobility assassins as they are in the middle of the map and can react to fights quicker and pump out enough damage to turn a fight if needed
bot- you have an adc/support bot because of its close proximity to dragon so you have 2 players standing by to quickly intercept an enemy dragon attempt, and the support/adc setup is because adcs are so item reliant and has such a weak early game that it helps to have someone who can soak up passive gold simply by being there and help the adc farm up as fast as possible
as for your setup, if the enemy reacts correctly and wards their jungle and is watching for you, especially down bot, it can completely ruin your strategy, say you are spotted clearing their red and your mid and bot laners are pushed to turret, if both of you are there, it ends up being 4v2 very quickly, with your mid and adc (who is very underfarmed from being bullied in lane in a 2v1) showing up late to a very unfavorable fight
not to say it cant work, but against any team who is semi organized, i dont see it working very often, leaves your dragon very vulnerable to quick grabs by the enemy team, and if you get pushed out of their jungler, that leaves 2 junglers trying to clear a jungle that already leaves one jungler having to build on a budget
also, it leaves your team hitting late game earlier from the deny that is undoubtedly going to happen to your adc... theres a reason most pro games end at ~25 minutes, thats when the adcs start hitting their real power