Blocklist

Honestly I would also like this but it would be quite unreasonable to add this.

The reason being, currently there is a set of filters that every server has, the listed filters we see. The users ID tells the server that it should use X-Y-Z filters for that user and any other allow/blacklist additions. It works and in a case of you changing location for load balancing or a problem would only require the new server to fetch the few blacklist/whitelists you have and you'd instantly be ready again. You wouldn't even feel this happen.

The problem with having custom filters would be that, it's possible ofc but it would require additional space and power to make it work. It's only a few mbs right not huge, times that by a few thousand, that's a few gbs but let's say on centeral points with a ton of users it adds up, what if the users connected server switches, instead of instantly fetching the few filters you are talking about a lot of users constsntly changing adding and modifying their lists. Again it's possible but would require even more servers and even more powerful ones at that to work. 

So they can just add more servers with addtional power to make this work right?

It would affect the end user and for counties with lesser currencies and inflation that's even worse a dollar could be a genuine difference maker in the user affording it or not being able to spend that much. Again in the US a dollar is only a dollar but in other countries it can be worth far more but even in the US,if you don't want this but still have to pay more it doesn't make sense.

So at the end, the required changes that they would have to do, it would make the service more expensive and give it a higher risk of failure with more stuff going on in general weather this be that the drives getting older with more use for updating the custom filters or just problems in general. 

I think at the very least the available blacklists should be updated. There's lists in there that haven't updated for well over a year. For a paid service this should be taken care of...