I truly, truly don't understand some people's insistence that leather soles are just as comfortable for walking as rubber ones. First, if that were the case, there would be leather-soled athletic shoes. There are not. Second, if that were the case, podiatrists would not be recommending people with foot, knee, ankle, hip, or back problems switch away from leather soles to rubber ones; but they are. Third -- and this is the most important thing of all -- if the OP has given it a good try and says they are not comfortable, who are we to insist that he is mistaken? Some of us may be comfortable in leather soles all day -- I am if I'm not doing too much walking on hard surfaces -- but that doesn't mean everybody is the same.
Angelicboris (I'm not doing the cap/small thing), those who have recommended rubber soles are absolutely correct. Both AE and Alden make great ones in conservative styles that would suit your needs very nicely. Some European companies do too, but they can be pretty spendy over here. Good luck.