I agree with you, myself being one of those people doing bulk lookups a few years back, BT was aware that I was doing and knew I was doing this for two years where my local MP told them that I had written an application that did checks for my area (well it checked all addresses on our exchange that didn't have fibre), only when BT said stop is when I stopped.
Now would I do all that again if needed, probably not.
I also think the changes that they have put in place including the captcha are a good thing.
The way I see it, they could of just locked it down for just ISP to use.
TBH I think it is now faster in displaying the page due to they are now doing it more better and correctly and the page is now reactive and works better on phones and tablets.
I think people will just moan due to change and nobody likes change, sure it looks different, but it displays all the required info so one cannot moan.