Though it is not a definitive grammatical principle, sentences with infinitive forms are often less awkward and wordy than those with the -ing (progressive forms). In this particular case, not only is "looking at" in choice E nonsensical, as to look at implies visual skills rather than logical considerations, but also the verbs using and attract are not parallel. Answer choice C, the credited response, correctly employs the parallel verbs improve and attract.

well, strictly speaking, a waterfront is not a way of doing something; it's a physical frontage that is just sitting there next to the water. So, literally, that statement is nonsense.
More importantly, if you compare that choice against choice (C), you should notice that (C) is more concise and better worded.
(That's the way you should make all decisions about "wordiness""”they should be relative decisions, not absolute decisions.)

be looking to do sth 力求做某事

用不定式表目的，look at是看。that指代的是communities，复数。

but可以做副词，表示仅仅，只有，如：
we can but try.我们可以小试一下。
There were a lot of famous people there: Tom Hanks and Julia Roberts, to name but two.只提其中两个人吧。
Trenton, New Jersey, is but one of a large number of communities. T只是很多个社区中的一个。

as a way for it表达wordy

that指代的是communities，应该用复数are

look at 看，is looking to 期望，力求

A.主谓不一致；its无法指代指代communities；as a way for it表达wordy；
B.主谓不一致；look at表示看，在此用动词不定式表示目的；
C.正确；
D.表示目的时，as a way of doing 不如to do简洁有效； its无法指代communities；
E.improving 和attract不能平行；

Trenton是主语，前面的with用来修饰主语。句意是a large number of communities在做和Trenton一样的事，Trenton是其中一员。如果仅仅是想表达Trenton在做什么，没必要加上a large of...