The problem with the smaller band saws is that because they are smaller (and generally cheaper) they are not built strong enough to handle the kind of tensioning needed to keep the blade straight when doing intricate work. A larger BS does allow for more tension.
I have the 10 in delta at my US address and it was difficult to make a "straight" crosscut on hard/grainy blanks even at full tension and slow feed. I could still flex the blade easily with one finger at full tension. I could make straight cuts, but it was a pain. I spent several hours fine tuning it, but it just isn't made to do what a larger BS can do. A larger BS can still use just as fine of a blade as the 10 inch ones can. The extra power of a larger BS also provides smoother flow of the teeth through the wood, which will also make it more accurate in more intricate cutting. Less power means slower cuts and less control - without considerable experience.
I will say that I know (and have known) some fine craftsmen who could take any machine and make it work absolutely great, but that takes experience and skill, and excellent eye / hand coordination to boot.