1...e5 is a good move but nothing threatning. Infact it is what white wants to get in a type of king indian position
1.g3!?

I have used it a bit, but now i don't think it's a very good weapon (in long play) for someone rated below 2000. The fact is that there are so many plausible answers that you will never get the same position. This is refreshing but also confusing, since it is difficult for a weak player like me to understand the various structures.
I think the variation suits better strong players trying to challenge his opponent positional understanding.
I also think the "this avoid opponent's preparation " argument is not very solid. Yes, your opponent will spend a few minutes in the early moves, but after that the position will probably become new and original for you as well, and your clock will tick as much as your opponent one. Also remember that there are not early pitfalls for black unless he overextends badly, so it's not that your opponent has to check a lot of variations before answering.
In blitz the variation is popular and sensible (i think), developing with a standard setup and using little or no time.

If the positions becomes new and original of course depends on how well you have studied the types of positions arising from the opening. Since I have played the modern defences/pric/accelerated dragon/hedgehog/KID/benoni/ + others which 1. g3 might turn into (depending on what both black and white does) I usually understand the arising positions from this opening quite well even though both black and white has a lot of different ways to approach it.
However you kinda go against yourself there bresando since first you say "this avoid opponent's preparation" argument is not very solid then you admit that this argument is in fact a good one by saying "he will take a few minutes in the early moves". If this happens it certainly seems like you have avoided the opponents preparation quite well and taking him out of book which is exactly what white was looking to accomplish. If the positions becomes new and original doesn't matter, it's the fact that you have taken the opponent out of book that counts and you can enjoy a normal game of chess.
Sorry my english is not that great, sometimes i fail to explain myself.
Of course your opponent is out of preparation, what i meant is that the average W player will be out of book too in a few moves, so you can harly expect a time advantage out of the opening. This is not a tricky gambit line where an unprepared opponent burns lot of time to avoid traps, B can choose simple development and he will hardly spend much time.
You have played the modern defences/pric/accelerated dragon/hedgehog/KID/benoni, yes but you're a very strong player! A weak patzer like myself has not the knowledge to handle such difficult sistems( particularly the very beautiful hedgehog is in my view a suicidal opening for someone wich has not a master ungerstanding of the game) . I used to play the Reti opening as W for 2 years (which is very similar in spirit to 1.g3) but since i have switched to move standard openings my results have improved greatly, since i understand better my positions. One day as a stronger player i will happily retrurn to g3.
I agree with you that you can get interesting games via 1.g3 ; i have good memories of many battles in this variation. But for a 1650 player like me every position, how classical it might be, is new and unexplored, while at your level i understand that you might feel bounded by theory and refreshed by playing simply a game of chess.
This is one of my favourite secreat wepoaons with the grob. I like to see players spend 5 minutes trying to think what to do when g3 is such a regular response. Whatever they play I have a wide range of moves to use, What do you feel of the move ?