I did want to post my opinions about each episode in turn, but I've been a bit busy and never got around to that.
Instead I think I'll write my thoughts as a spiel about the series so far.
I think Telltale have made what (given the reaction) turned out to be an incredibly brave move here.
Certainly I can see points on both sides. Point-and-Click is definitely a superior method of control to using WASD or a Gamepad for adventure games. However using the Gamepad-style controls gives more freedom with camera angles, and helps ports to consoles.
To be honest, I don't think Telltale deserve the 12-page rage threads that they've been getting over the control system. It has flaws, but after sticking with the series and comparing #1 against #2 and #3, I can tell that they've slowly been working on them.
For example, the occasional camera angle bugs that popped up in #1 are not present in #3, or Telltale have tweaked their key-layout (e.g. moving the select button from the Y button to the triggers). All of this helps.
It will be interesting to see what Tales of Monkey Island will be like in this respect. As much as I want Wallace and Gromit to succeed, I wonder if Telltale were using it as a kind of sacrificial lamb to test their new control layout.
Length and difficulty
Wallace and Gromit is definitely more "for kids" than any other game Telltale have made so far. Unfortunately this rather does show in most of the puzzles; most feel like just going through the motions with no thought needed.
Interestingly in #2 and #3 Telltale started making the puzzles steadily more clever as the games progressed. This had an interesting effect, where initially I go from being put off by the game (with the fact that I've paid money for the thing being my only motivation for playing on) to suddenly getting into it. It's probably a good idea to keep the initial puzzle simple to give people a warm-up, but I feel the step up needs to happen sooner into the Episodes.
I feel that the characters are a bit hit and miss.
Telltale have captured Gromit almost perfectly.
Wallace seems a bit off... he's a lot more penny-pinching than he is in the films. His character seems to have been a little skewed to allow for all of the puzzles.
Major Crum is way too clichéd, and also suffers from having to acting in various arbitrary ways to suit puzzles. Also, is was he in the Army or the RAF? It's not usual to have been in both, so make your mind up which, Telltale!
Constable Dibbins is pretty much just as clichéd as Crum is. Both Crum and Dibbins strikes me as a real missed opportunity, as someone with some knowledge of the British armed forces or the police could have written us very interesting and more realistic characters. I guess there are worse offenders for things like this out there though. (Shadow Hearts, anyone?)
Having said all of that above, Telltale then go and make up for it by including Mrs Gabberly and Mr. Pannear. Both are wannabe-English clichés in their own way, but they aren't actually very clichéd as these types of character are not included very often.
Overall, unless the last in the series does something extremely spectacular I don't think Wallace and Gromit is going to be remembered quite as fondly as the Sam and Max or the Strongbad series will be.
Which is a shame in a way, because when you cast a technical eye at the game there are a lot of things here (the environments, the cut-scenes...) which are really impressive.