Had you booked your vacation with an agent and not with Hotwire, they would have told you about the pre-existing conditions. We have over 800 agents around the country and have been using Allianz for years. They are very good and we have had very few problems while selling tens of thousands of policies.
Based on your comments, it is clear to me that Hotwire definitely did not give you all the information in the first place and did not explain how travel insurance works. This exact same outcome would have happened with just about any of the travel insurance companies, not just one.
Pre-exisiting conditions of you or anyone in your immediate family, whether they are traveling with you or not, is covered provided you purchase the insurance at certain times in the process. This I know for a fact after selling it for more than 11 years.
However, with all that said, some of the bigger players in the game have negotiated special policies for their clients and obviously some policies are better than others. It's quiet possible that the policy purchased through Hotwire is a special policy that is cheaper because it does not offer specific coverages better policies will cover. That is not the insurance company, but Hotwire. Again, it is Hotwire that should have explained all the nuances of the policy so you can make an informed decision as to whether it would cover you in your specific situation or not. If the policy does not cover what you wanted it to cover, that is the fault of the seller for not explaining that to you, not the fault of the insurance company.
For example; some cruise lines sell a travel insurance policy that provides credit towards another cruise should you have to cancel instead of providing a refund. If you want a refund if you have to cancel, then you don't buy the insurance offered by the cruise line - you purchase independent travel insurance. But if you purchase the insurance offered by the cruise line and have to cancel, you can't complain about the insurance company for not giving you a refund. It's the fault of the cruise line for not explaining it to you and it's your fault for not understanding the policy. This is why it's so important to work with an agent who has your best interest in mind.
We've dealt with alot of travel insurance companies and Allianz is definitely one of the better ones to work with. You just have to know the policy you're buying as they offer several different kinds of policies.