Look you're probably not going to like what I have to say so remember that I have been kind, friendly and patient and that it's always bad form to shoot the messenger.
You cannot edit your templates due to security reasons - please, please read the FAQ's and the documentation.
Now quite aside from the position you have taken there is another point of view. The purpose of wordpress.com is to provide a multiuser blogging platform for those who do not know how to code. Yes, take a deep breathand read that again - it's for those who do not know how to code.
Those who can code have the option of getting their own domains and downloading free wordpress templates and adjusting them to their heart's content on their own servers. They also have the option of going to webhosting, which is not expensive.
On the other hand, those who cannot code and who do not wish to be bothered with all the blah, blah, blah and the never ending adjustments do not have options. That is why this multi user platform exists. It exists for people who just want to blog.
The bottom line is wordpress.com is what Matt wants it to be so, the way I see it you have several options.
Knowing that happiness is a choice one makes between one's own ears you can
(1) make the happiness choice by accepting wordpress.com for what it is, be grateful for the free ride as well as the constant improvements to this less than 1 year old MU platform and focus on creating blogging content;
(2) you can choose to be quietly unhappy and focus on creating blogging content;
(3) you can choose to be unhappy and loudly bleat your unhappiness out on the forum and distract yourself away from creating blogging content;
(4) you can move to a webhost and for a modest fee you and download a wordpress template to fiddle with free of charge;
(5) you can download a wordpress template to fiddle with free of charge on your own server.
On the other hand, people like myself have only one choice. This is why we bcome "testy" when we hear those with so many choices mounting high horses and trying to run the calvary.
Please take note that I've said all of this to you in good humor and I hope you will accept it in the spirit it was delivered. Make the choice to be happy, okay. :D