Here's my personal take - in this instance, I think the retina MacBook or MacBook Pro are the best matches, with the MacBook Pro being favored if its slightly larger form factor and price is acceptable because of its greater flexibility, and the retina MacBook being favored if ultra portability is the most important factor.
I am a huge proponent of the MacBook Air, but a major reason is because of the great deals on it which, as you have observed, apply more to the 128 GB models than those with other SSD sizes. The biggest advantages you get here will be a better battery life (Apple seriously underrates the runtime here!), a somewhat lower price, and internal expansion capability through the SD card. The keyboard design is arguably more durable, and you may or may not like it more/less than the new design. For an on-the-go User, MagSafe 2 can be really nice in its ability to protect the computer from a fall (but, IMO, it is quite a bit less durable than the USB-C design that has replaced it.) It's IO situation is superior to the retina MacBook but inferior to the MacBook Pro, IMO. With that said, Thunderbolt components are expensive (but, by having that TB port, you can connect to an external display and two USB devices without needing a dock.) Some of the extended warranty w/ accidental damage plans are cheaper with this model than other Apple portables.
IMO, the 2017 retina MacBook is an entirely different beast than the 2016/2015 versions. It 'feels' extremely (almost shockingly) small compared to the 13-inch Air, but you can see more on the screen IMO because you can use a smaller font since it is more legible with the retina. The 2017 retina MacBook m3 has CPU benchmarks quite a bit higher than the MacBook Air's i5!!! (the 2017 rMB has made dramatic CPU gains over the 2016 rMB.) It's keyboard is a lot better than the 2016/5 generations IMO. It's industrial design is awesome, screen is great, and form factor is spectacular. The Trackpad is far more advanced than the Air. For the highly mobile user, this is a great computer and IMO the 2017 rMB has become an outstanding option for someone who will purchase it as their primary or sole computer, even if performing moderately intensive work. It gets excellent battery life. Several customers I have spoken to who have upgraded their 2015 MacBooks are simply delighted with the progress made in two short years.
My biggest hesitation regarding the retina MacBook is not that it has only one port, but that this port is legacy USB 3.1 gen 1-5Gbps. If you want to connect to an external SSD, external HDD, flash drive, SD card, external display, or other external devices simultaneously, even with a dock you are limited by the measly 5 Gbps bandwidth - which a single SATA SSD will completely consume. The MacBook Air is capable of the 20 Gbps Thunderbolt 2, and the MacBook Pro is capable of 10 Gbps USB 3.1 gen 2 and 40 Gbps Thunderbolt 3. If you do not use a lot of external accessories and do not intend to, this isn't nearly as big an issue. Buying a larger SSD on this model may be advisable given the limitations you will face with external storage.
The MacBook Pro has a slightly better screen than the rMB, better speakers, a considerably faster CPU (the base nTB's i5 is a beast), faster GPU, faster RAM, a faster SSD, and modern IO with USB 3.1 gen 2/Thunderbolt 3 (plus you get two ports.) This model is the most "future proof", if such a term has ever really existed, and it is by far the most flexible of the three options should you wish to use external displays now (or in the future as 5k becomes more dominant.) As you kept your last system for 6 years, having the extra CPU/GPU power probably is not a bad idea if you plan to keep this system for a long time as well. With this system I think having a smaller 256 GB SSD represents the least risk because of its ability to take advantage of future high-speed USB 3.1 gen 2 external SSDs and flash drives, which neither the Air or rMB will be able to fully utilize (not to mention Thunderbolt 3 opens up doors to external NVMe SSDs and external GPUs, should you ever desire/require.)
