Glad you enjoyed it. Obviously this is just one redditor's opinion, but here are my responses to your concerns.

My chief concern is that, your constitution has essentially given both the monarch, and the legislature far too much power.

Well it should be noted that the constitution isn't really spelled out in my post. It would essentially be whatever the nation was willing to embrace for that society. So, the constitution for say Alaska might highly curtail the powers of the national government while the constitution for California essentially gives him free reign. That being said I did make the constitution easy to amend which I will think about.

If Congress could impeach a monarch(which lets be honest that's what it is) then he is under ENORMOUS pressure to submit to the populist whims of the House of Representatives at all times, as well as the oligarchic desires of the Senate.

Obviously this is a balancing act, however I do want the president to be responsive to the wills of the people and I feel that 2/3rds of both the house and the senate is a pretty resounding signal that the current monarch is either unwilling or incapable of serving as the embodiment/servant of the people, especially considering that 2/3rds of the Senate would have been appointed either by him or one of his recent predecessors.

Ideally I think the monarch would best avoid partisan politics by trying to insulate himself from direct decisions via his cabinet.

Another reason I wanted to make deposing the monarch a real possibility is to prevent revolution. In virtually all Western nations monarchies have suffered forced abdication, beheading, or neutering of their powers to the point that few exist beyond serving as mere figureheads. I feel that this system would serve as an outlet for discontent and preserve the monarchy as much as possible.

Having him be the only one able to initiate legislation is a dangerous idea. The king would be blamed(rightfully so) for any bad laws that the people despise, and would be subject to deposition.

But see I want that to be the case. One of the benefits I see of having a singular ruler is that there is a much clearer spectrum of accountability. No blaming the Republicans, Democrats, the President, etc. It will fall solely on the responsibility of the monarch, and his job will be to govern wisely.

I would insulate the monarch from partisan and popular anger by having him appoint(truly appoint) a head of government, who acts on their will,

In my system that is allowed at the monarch's discretion. He is free to appoint as many ministers as he likes (although they can be vetoed by the senate) and I would certainly expect them to be doing the brunt of the executive/legislative work.

whilst also broadening the scope of who can initiate legislation(anyone in either house).

My great concern with that is that you'll end up with the corrupting influence of partisan politics and special interests as well as the conflict of whether or not the monarch wishes to support a proposed bill. I feel that the public will have plenty of methods to propose ideas in the public square to wish the monarch could/should respond appropriately. Also, they have to potential to filibuster/reject legislation from the monarch unless compromises are met, and lastly the lower house has a great deal of authority to repeal past legislation.

feudal government

I personally prefer a more feudal government for a few reasons:

• It allows the control of a large and diverse empire. I personally don't see the US having been able to have been controlled through a unitary state model. New England, the South East, the West, etc. would have certainly attempted to secede.

• I feel the nobility would be insulated as the main persons in charge of state governments would be state nobility. The reigning duke would be someone whose family was chosen to represent the will of the people (so like in Hawaii I would have installed Queen Liliuokalani, and in New England I would consider installing the Adams family, etc.) and other than that none of the monarch's nobility would have any control of state politics. Rather, the nobility at the state level would be controlled by the Duke instead.

allows the people to slowly get used to a new ruler.

Yes, and my main concern hear was making sure that the withdrawal of power was as predictable as possible. People know when King X is going to turn 75, but they don't know when he'll die.

I'm also a big fan of the monarch having the sole discretion over foreign policy.

I feel I should clarify that while he does have sole discretion over foreign policy (save declarations of war), he might still require the necessary support from congress depending on the nature of the treaty. For instance, King Truman could pretty much have signed all of the agreements for WWII, however King Polk would have required Congress to approve sending money to Mexico as the treaty of Guadalupe-Hildalgo required.