So right now, it's a working business model vs escrow which isn't used in raffles that I know of. Keep in mind that Satoshi Dice and other big risk formats don't have escrow too. None of the big bitcoin casinos have that (correct me if I am wrong).
If your site is already trusted from this community then no need have an escrow and that part I completely agree. But do you think your site and you trusted members on this forum?
Whatever is your explanation for not using escrow investments are better compared to investing on new site.
From my research on other raffles, like Princess Margaret Lotto for example, when they get let's say 10% of the revenue in their bank, they begin to spend it on advertising and operating costs.
If you start using your 10% and if you don't reach your target then what happens to the funds you already raised?