The game started to get pretty fun toward the end - building off of the case 4 made the reveals substantially more interesting. However, those first three cases...
The two big issues I had with the game were very stilted dialogue and the extremely slow pacing. At several sections I felt the path to arrive at a conclusion was very convoluted, and often felt redundant to earlier dialogue. Ex. You observe something, Miles and co. say "huh! This clearly contradicts X, so maybe Y happened..." Then you must go to the logic menu to concise l conclude Y ogether then beat around the bush for three rounds of argument to show Y. Meanwhile, the dialogue reads:
Whoever: "You have no evidence to prove Y at all! You can prove nothing! Z actually occurred!"
Miles: "(Whoever says that I have no evidence to prove Y... but there's no possibility for Z because of that evidence...)"
"Ho ho ho... of course, I would never make a claim without evidence. The evidence that Z didn't occur is..."
*present evidence that Y clearly occurred*
Whoever: "That a shows nothing, dumbass!"
Then, I look through the evidence list to prove Z didn't occur, which let's me go to intermediate conclusion W, then another witness briefly jumps in with a quick "What I Saw, Pt. 3", then you can finally present the first piece of evidence Y occurs.
This general format, with awkward dialogue, really brings the game down. By Case 5, though, the intermediate steps started to be less excruciating, and the setup started to pay off.
Now I've played AAI2, and the first case was way way better paced than anything in AAI. A big part of that comes down to Mind Chess being a much more efficient way to get information and a good substitute for the psyche lock mechanic. Generally, the testimony battles were much less excruciating with fewer pointless steps.