yea sure that may work in Hawaii when there is no current, surge, or wave action. Try diving in North Carolina, they won't even let you on the rail without your fins already on, cause if you go over the current and waves could easily leave you a long way from the boat before you realize what happened.
the OP, climbing a ladder and walking on dive platforms with fins on can be tough, but mostly it requires practice and patients, time your movements with the waves and take small steps with a firm grip you should be ok. take a good look at the dive platform, sounds like it could use some more non-slip on it, which should help some, mentioning it to the operator is probably enough, afterall he wants you business and if you feel your safety is threatened he is probably more than happy to spend $10 on some non-slip pads for the platform if it means you return to his shop.