You know, it's interesting. This is probably, if memory serves, the first siege tower that Lego ever built, and they have yet to improve on the design. Course, that's not so much the brilliance of this one's design, as the horridness of the others.
On that note, the design of this set reflects the more basic build that sets had back when this was released. The wall element's design works, as, I assume, it is meant to be intergrated into other sets of the era. I'm sure many youngsters would have enjoyed having a bit more wall to add to their city. The siege tower itself is a bit bland perhaps, but that might just be the colour, which as Jojo said, was what they used for wood back then. The design fits with the rest of the era, so it's all good I guess.
Meh, it's all what you are after I guess. The four figs are great of course, and with their relatively non-factional look, it makes for a good army builder. Then you get some bricks, a brown ladder, so plates, and if you are interested in them, so wall pieces. Like I said, it's all what you are after. I sure like anyway.
If a kid has other people with which to engage these knights, it's great for playabilty. And even if he/she doesn't, it still a decent model. All the elements are there for some good fun. A wall, a siege tower, four armed men with allegiances unspecified, pure classic.
I build, therefore I am.
Brave words coming from a guy called grapenuts.