I like a lot the way you describe fragrances, and I am so pleasantly surprised that you included Eau de Rochas in the list of "Effortlessly Chic Spring Fragrances"!
As you say, I also feel that this scent is under estimated. Some find it too classic or even old fashioned, too recognizable. The truth is I can't find any other eau that suits me as much as Eau de Rochas, and I have tried so many!!
I thought perhaps can could suggest another scent as clean, refreshing, with this "light chypre" touch as Eau de Rochas, but a bit more "updated" or modern, something in the same family but a bit different.
Eau de Rochas was originally created as Eau de Roche after WWII in 1948 under the tenure of Edmond Roudnitska at Rochas although I could not find his name associated with it for sure. It was recreated for certain in 1970 by Nicolas Mamounas. The fragrance has a quite unique smell despite suggesting transient, crystalline lightness and freshness. It would therefore be a bit of a challenge to find a convincing substitute...
Its scent is fresh and crisp but also fruity and with a touch of elegant austerity from the moss. If you want however to explore the range of olfactory emotions it can trigger in you, I can suggest a few fragrances.
If you want to find some of this limpid freshness and clarity as well as hint of bitterness, I'd suggest Hermès Eau d'Orange Verte, Hermès Eau de Pamplemousse Rose but also the classic Cologne 4711. You can also consider Sisley Eau de Campagne and Dior Eau Sauvage by Roudnitska.
A harmonious contrast of fruits with crunchier notes can be found in Fidji by Guy Laroche which although viewed more often as a green chypre has aromatic affinities with Eau de Rochas, plus it smells very good even in the modern iteration.
Another perfume I'd suggest trying is Cristalle eau de toilette by Chanel which this similar gray-green celadon-colored perfume owing to the presence of light, dusty and bitter mosses. Prada Infusion d'iris has this same quality of being the remembrance of an eau de cologne: it is crisp, fresh and puts front and center the iris found in the base of Eau de Rochas.
If you want to smell trendier, the new Eat by Fresh takes a similar citrusy crystalline accord but turns it into a a gourmand scent with a very nice chypré lift, in case you wanted to test your olfactory limits in that direction. It is actually and counter-intutively quite close to Eau de Rochas in the drydown especially. Citron de Vigne by the same brand might quench your thirst for freshness as well.
In the niche area, I'd further suggest you test Frapin L'Humaniste and Ginestet Sauvignonne for their pale, white-winey and fruity quality.
I hope that readers will offer more suggestions (the spam situation has got so bad, it's best to email me directly at this point and I'll post the comment.)
All the best,