IMHO there is definitively a need for Lvl 0 monsters. This quick fix would make lvl 1 a lot easier. (in fact, we have a nearly level 0 monster minion: the human goon)
It really would be no problem at all lowering the level to 0, an easy fix. Level 1 is really that hard, because you can´t encounter monsters that are under your level, and you have no utility powers that can help you. Lvl 2 utility powers are generally very very potent in some cases... so it makes a great difference.
To the damage problem: Yes, Lvl 1 is hard, but 4e was regarded as easy mode D&D, because of high hp and damage... no, it isn´t... HP and AC work differently than in 3.5. (Not that a TPK could happen in 3.5 very easily at level 1)
So lvl 1 is nearly as deadly as in previos editions. Not much less deadly, but definitively not more.
At higher levels i once again want to explain the effect of increasing damage:
Problem:
-> monsters did ridiculous low damage, especially some brutes. (A giant dealt less damage with his club than a lvl 1 fighter)
-> solutions of many DM´s increase monster level to deal with players (instead of adding more monsters which would have yielded a better result in general)
-> Monsters hit very well but still do low damage. Monsters AC also skyrocketed and are hit not so often in return, their hp also increases
-> you are hit nearly all the time, monsters are very tough to get down and combats often feel like carving thorugh a giant bag of hp
solution:
-> increasing damage (often to reasonable values. A rogue with a dagger may do more damage than a brute with an axe... but special attacks do more damage on CA or allow slides, where special attacks of the brute knock prone or push)
-> Monsters of equal level are threatening. No need to adjust as a DM
-> Monsters in generall can miss, but a hit feels like a hit, not just a scratch. Non damaging effects are not always applied, but only sometimes. HP and AC of the regular enemy are in a range, that using a daily or fokus firing one down actually can work, which makes tactical combat a lot more interesting.
-> Monsters of lower level are still threatening, but quite easy to focus down. A good alternative to minions in some cases.
-> here again I want to stress how nice it would be to be able to scale down monsters to level 0 in the monster builder. As Monsters 1 level lower are especially interesting as they would pose an interesting threat to lvl 1 or lvl 2 players.