Speaking from practical experience you are underestimating the difficulty of persuading a cleric/wiz to part with 2 GMW a day. I a group with both a wiz and a cleric, I was only rarely able to persuade them to give me two for my archer. There are a ton of extremely useful third level spells and they are not going to want to spend a sigificant chunk of them simply buffing the archer so he can kill everything while they sit back and twiddle their thumbs. Other characters are also going to want buffs and GMWs as well, especially if you are the only one getting to do anything because of your buffs.
Your character also takes advantage of a flaw in creating high level characters. You don't have to take the feats and stats that would enable you to survive until you hit the level your character was designed for. Your exceptionally high wisdom is largely useless until you hit level 7? of OoBI, which is a substantial discouragement to creating characters of that type at 1-3rd level and then trying to get them to survive up until you hit sufficient level for your "broken" combination to actually kick in.
Unless you have an outragous number of high stats you probably also don't have very good HP given that you are an Elf and have put your two highest scores in to Dex and wis. This does mean that you are susceptible to being taken out on the first round as you probably only have 65-70 hp, given your -2 con mod (assuming average rolls and no stat bonus). There are a number of monsters at those CR ratings that can crank that out in a single round (Giralions and the Mooncalf in Nightfang Spire spring to mind...).
Furthermore in my experience running an archer, you will only get that <30' shot in about half the time, which means that your bonuses do drop substantially a significant percentage of the time.
