Daniel, I quickly skimmed this whole thread and thought I would give my input. For a little background, I have lived my entire life in Iowa and have been bow hunting for 15 years. I have never lived or hunted in the areas of the state that are considered "the best of the best", so you have an idea of where my experience is coming from. I have bounced around a couple different areas of the state for my schooling and now live and hunt in the central part of iowa just north of des moines.
First of all, like others have said you would be nuts to leave the hunting and diverse opportunities you have in WA, I can see your dedication to just whitetails and understand why you would be willing to leave for Iowa.
Second, you are completely right about the economy and job opportunities for young professionals in Des Moines. The metro and suburbs are booming and growing rapidly, with that said the hunting near dsm is proportionally declining as far as access.
I don't personally know how private land access is in the prime areas of the state, but I have experienced much difficulty finding good private ground where I have been, especially long term access due to moving around.
Therefore I have been hunting mainly public ground around central Iowa for the past few years. Yes, there is a good amount of public along the river bottoms, although it pales in comparison to WA obviously. With as much ground as you cover I would think if you put the same amount of time in over here you could easily cover every square yard of public ground available within a reasonable drive every year. Yes you should be able to find some mature bucks and probably know of some 160+ every year on public. The top end bucks, hard to say but I wouldn't think it would be unreasonable to at least find a 200 on public every 5 years or so. Killing those deer is a different story with the much higher hunter density compared to WA public land.
That being said, this past year I had one 160 buck on camera and saw him from stand, and knew of a buck said to be pushing 200 on the same piece of public. Problem is, everybody else knew about them too.
I will close saying thank you for your service. Iowa is a great place to live and raise kids, and yes the DSM economy is very strong. I live in Boone and work in Polk City if you need any more information about those areas of the state feel free to give me a shout.