Senders name or email? That has always been an option. Has attachments? Been an option since forever. tags? Since forever. date? Available since forever.
Suppose, for example, I have set up a subdir for conferences. That subdir contains a bunch of subdirectories for individual conferences. I know the e-mail I'm looking for is stored in there, because it relates to a conference publication I wrote. However, that subdir itself is "empty" as far as gmail search is concerned (because it's a "tag" rather than a true subdirectory).
The net effect of these hollow imitations of directories is I can either target the search to a specific tag, or I can search throughout my entire collection of messages. (Or, I suppose, I can tag every e-mail with every single sub-tag represented in the directory hierarchy I have mentally set up, just in case I might want to search for it someday.)
The gmail ideal, of course, is that I abandon the notion of directories altogether, and just let all my messages stew in the ocean of e-mail that one accumulates over the years. Supposedly their "powerful" search capabilities will help me find what I want. In my experience, though, under this approach most reasonable searches produce multiple pages of possible matches. This, of course, is hardly efficient.
It would also be nice if I could perform a search and then pull out that page of returned results into a separate screen/window for ongoing reference. Often when I'm searching for something, I'm looking broadly for resources or related conversations, rather than for a specific message.
Another place where I feel gmail search is brain-dead is its lack of regex capability (which @devdas has already mentioned).
Separate screen of search results is just another tab in your browser - that's actually a vote in favor of web based gmail.
To make my example explicit above, suppose I have a "directory" structure with dirs like `conf`, `conf/iaq2016`, and `conf/gmu2012`. Then a search in `conf` will not turn up results in `conf/iaq2016` or `conf/gmu2012`.
Believe me, I check this once every few months, always hoping that google will have improved their "tag" implementation.
I do appreciate your tip about multiple browser windows, though. In general, I don't like having multiple windows open to the same application-- but that's my problem, and not a design flaw in Gmail's search.
For reference, you used to be able to do this - https://code.google.com/p/chromium/codesearch - with an archived cross-section of code on the Web.
I wonder if we'll ever be able to do regex Google searches in the future, or if AI/machine learning will make that sort of flexibility redundant by the time the hardware would be able to handle it.
But seriously, all these hard core unix fans seem a little odd here. Gmail search has always been powerful, and is even more powerful now. It sounds like a case of user error if it isn't working for someone.