As long as it's not to hot in your place then it should be fine as is. Everything is spaced out pretty nicely. Although personally I would think of moving the NAS, Modem, what looks to be internet phone box and power strip to the lower part of the shelf. Use a hole saw route the ethernet and power cables to the phone and wireless router on the shelf where they are at now. Prolly wouldn't make a difference temp wise but would look much nicer. Especially since you plan on leaving that open.