There are plenty of other European theme parks which offer large scale coasters and far better experiences than Merlin do. I haven't visited a Merlin Park/attraction for almost 2 years now because they are run like utter trash and I have no desire to give them any money anymore when they offer so little value for money in terms of customer experience. I would have agreed that the offering is a bit lacklustre in the UK, however Blackpool PB, Paultons Park and Fantasy Island are now all heavily investing in their parks and these parks offer far better experiences than the Merlin parks do(as well as having much nicer theming/atmosphere etc in Paultons). These parks are going to continue to expand and will hopefully soon separate themselves from the rest of the field in the UK scene.
Looking in the whole of Europe however, I struggle to see how there isn't much choice in terms of parks with large scale coasters. There's Phantasialand, Europa Park, Liseberg, Grona Lund, Efteling, Parc Asterix, Efteling, Tripsdrill and many more parks which offer great theming, atmosphere and experience as well as good coaster line ups. Not to mention Toverland and Walibi Belgium are now on their way up and heavily expanding too. IMO the likes of Gardaland and Heide Park are easily overshadowed by these other fantastic European parks and on the UK scene, Paultons and BPB easily overshadow the other merlin parks on the UK scene (thorpe, alton, chessington).
Merlin have just made a mess of their parks, especially Thorpe, which has such a lack of direction or any concept whatsoever of how to run a theme park. First, I'm a celeb, then angry birds land, then DGBTROTD, then Walking Dead: its just an utter mess and utter trash in my opinion too, I have absolutely no desire to go back there whatsoever.
There's two good things I can say about Merlin at the moment:
1. Heide Park are making an effort to restore Colossos instead of tearing it down.
2. The theming and effects on Wickerman actually look really nice(although we all know the effects aren't going to last long at a Merlin park).
However, neither of these factors makes me want to go back to a Merlin park in the slightest as the parks are so badly run with slow operations, oversold fasttrack etc that it's just not a fun day out anymore. Merlin parks have really lost their charm IMO since Merlin have taken over from Tussauds and I'd much rather visit better alternatives within the UK and European industry.