You have some good points.
I could relocate my Wifi routers to a more central position in the home. If my wired connections were all set up. They are not at this time. I do have an unmonitored 24 port gigabit switch as well as CAT5E home run wired to several points in every room. Eventually, when I complete the remodel, I will be able to connect everything to hard wired gigabit connections - if I want. Right now, connecting up to hard wiring is not the priority. By the time I am done, it will be a dinosaur that is useful only to those of us who want the utmost in security. The world seems to be going to wireless LANS which I implemented only as a stopgap till I got my wired network up.
Since I don't have a wired LAN yet (it's really a SAN) I have to make do with what I have, which is a cable internet connection at one side of the house going to a modem and a couple DIR-825 dual band WiFi routers.
I live in a multi-family dwelling where other people have WiFi networks. I noticed that one of the other people has a Linksys router (it's an older single band "g" router) that puts out beau-coup signal. It puts these DIR-825 routers to shame, even with 8dB High Gain antennas connected (stock antennas are 2 dB). I thought for awhile that it was just that the "g" routers put out more signal but I tried my older D-link WiFi router with high gain antenna and it was nowhere near what is coming out of that Linksys router. I have not asked the other person whether they are using dd-wrt or some other open source firmware to drive the output signal of their router so high. I do know that the router seems to be stable and has high up-time (the signal is there every time I check). I want to know how to make my routers as stable, and with as high signal output as that linksys router. I can't say anything about the signal quality of that Linksys router in how it receives signals, only that it puts out a lot of signal strength. There is only one Linksys router in that place and there are no other AP's or repeaters (I know this because I own the entire building and his unit is too small to warrant a repeater, or AP).
I looked at the standard D-link FW and I already have the power settings at 100%. With the other difficulties I have encountered running the stock FW and trying to get the USB ports working with an external HDD, it looks like dd-wrt or open-wrt may not be such a hassle after all since they seem to address both these issues (at least on the Rev. B router anyway). I may have to stick with the stock FW on the Rev. A router.
I have been looking at some of the new "ac" routers and, even if they do put out a stronger signal, there is little increase in the 2.4GHz bandwidth. It's all in the 5GHz bandwidth which has high signal attenuation and is more ****e to interference. I like having external antenna which provides me with the ability to alter the configuration the way I like. If I wanted to put up with a huge powered antenna mounted on my wall, I could probably get all the signal strength I desired, even outside the building, which was the intent of my post on this. I can't do that with a WiFi router that has internal antennas.