Well, I followed up 'mediocre' with 'underwhelming', which might be more accurate. I also mean mediocre compared to what these guys have created before. I've listened to every Neal Morse, Dream Theater, and Flower Kings album* and while I don't think Kaleidoscope would be at the bottom of my list if I ranked all the the albums they've done with their main projects + TA, it definitely wouldn't come close to being top 10. I think it's mainly because the bar was set so high for me with their first 2 albums, and then The Whirlwind was even better imo. Of course, I'm not one of those old prog heads that think the music is bad just because it has some resemblance to the big prog acts of the 70s, because I think they bring elements to the music you would not have found back in those days. I do, however, kind of see where they might be coming from, you've heard all that kind of music so much and after a while you realize it doesn't venture out beyond a certain range of sounds and styles, and perhaps you find it 'dated' because you grew up at that time, perhaps. I do seek out music that is "progressive" more than I do 'Prog" or "Progressive". I have no problem calling an album that clearly showcases great musical ability, chops, sense of melody, long song lengths, etc... 'mediocre', if I feel like I've heard it all before in other albums, and done many times better (all IMO of course.) At the same time, TA4 came out at a time when I wasn't listening to much of any prog rock related music. I actually haven't been diggin' much of anything from the 4 main members of Transatlantic this past decade. I loved Banks of Eden, but have been underwhelmed with everything else Roine Stolt has released since 2007, sans The Whirlwind. Not sure what's been going on but it seems like some of that Roine magic has faded away. Portnoy hasn't done much I'm interested in outside Neal's stuff, and with Neal I think I just got burnt out on his sound so I haven't listened to him much in a while. Since Testimony 2 I haven't been crazy over his albums solo or with the Neal Morse Band since, but they seem just fine/standard fare for Neal's music and I'd probably enjoy it more if the Morse mood strikes again.
*I actually haven't gotten around to checking out the newest Flower Kings or the last 2 Neal Morse projects. Not really into Marillion based on what I've heard.