All this is based on my opinion and personal taste about themes, including needs for better attractiveness.
kompoz: Theme who have potential, light, fast load. Slider is fine, posts below slider with some blur effect which I have never seen before, that's ok. Structural it could be better, make some types of posts with bigger thumbnails, make text which marks categories,
Recent Posts,Recent Comments, different from titles (all caps, bold, different color). And make links change color on mouse cross. Boxed layout could be used too.
megamax: my favurite, this is so good theme, and should be used for some business, portfolio or similar things, with pages for offers products etc. I see it like theme for web hosting. Only thing I would change is bold text on mouse cross, just text, not titles. And provide this theme in several types of color should be fine.
inzagram: Very interesting theme, it looks like social network but it's like blog. Definitely this should be blog theme, put somewhere author box, left or right with info and picture of blogger, and central part of theme would be this wall, like social network wall, where author posts shows.
allshop: I think that idea of this theme is shop and review products. However if it is for products I think it should be with smaller thumbnails and posts so visitor have more and more products to see. I see cart, checkout so user login should be big and visible, on top of course.
For all themes: On every theme bottom slider on my browser shows up, you should check width of themes and make that responsive. Also all content are wide, so I think you could try boxed view to make it less wide. In general, your work is really good, it's not easy to develop all this, just include little imagination. If you need inspiration take a look on other themes already popular and try to make something similar, I am sure it will work. People likes picture motions in thumbnails, sliders, colors so use that and you will make it good. Just continue to work, success will come 100%.
Good Luck!
