What makes retros "good" in 2019? before it was all about the custom furni, lately ive been seeing custom clients.. and custom CMS's (VERY FEW), What would attract you to a hotel?
Honestly, I don't think anything really attracts users these days, to be honest, it's kinda just you as a person and who you have working with you. There's hotels that get 30+ users and they're using a basic Arcturus setup and a CMS that has little to no customization with a logo generator that isn't even habbo related. After talking to the users, they just play there because they like to play there, has nothing to do with what they have.
The Community is the most important. I've seen hotels that weren't updated for years till now. They had like 200 achievements but they had a community and a great economy.
Of course you need something to show users that you're keeping it up to date but only couple of furniture and clothing should do it. You should give some value to your rares and special items. I'm not talking make items 10mil the first day you open like no one got them credits. A welcoming community a very friendly and professional staff team and of course a couple of people that will advertise (people who are popular in the Habbo Community). Also give others the chance to become staff by Hosting Events and being active most users will come for staff at first but then after you have a bigger community people will come visit and if they like it they'll probably stay. Also try to track everything down so you know your staff aren't abusing their powers.
As a leader you should be working harder than everyone else that way users will know that the hotel is in safe hands and the ownership is always willing to make the Hotel a better place.
That's all I can recommend. And in the free time you can do some custom things as a bonus.
But I don't think making Designs or doing RP things is important visitors will come see it they'll be like cool but won't continue playing the next day because it's too boring.
Of course it's good to have a unique hotel however I think the first step is for you to have a community that is willing to support your hotel and you're willing to treat them the right way.