Some of my thoughts/trivia written down w/o any formatting.
Sestola - this all i believe is one of many ways to reach Pian del Falco that's just above the town but below Passo del Lupo. I will need to look up this stage more closely as a lot of the roads in this region were either broken or outright abandoned so maybe some redevelopment happened, which would mean more options for the future (Le Polle/Piane Mocogno/Febbio).
San Giacomo sul Ascoli Piceno - the same climb as in 2002 where a certain Cadel Evans came into prominence. Interestingly they're taking Forca di Presta, which i thought was very damaged. Forca di Gualda was last year in Tirreno and nearby you have potential MTF finishes at Monte Prata or Frontignano di Ussita.
Guardia Sanframondi - Bocca della Selva is the 2nd most famous climb in the Matese massif (after nearby Campitello Matese). Interestingly, it's the other way which i thought would never happen. The descent to Cusano Mutri/Telese Terme is long, quite dangerous and it may be on not the best of surfaces. If the finish was in Cusano Mutri or Telese Terme and maybe full Campitello Matese beforehands this would be il Falco terrain all day long. For me personally a very interesting design.
Campo Felice - Another stage with unususal descents (Godi and Fonte Ciarlotto). I don't believe you can do any better with the roads you have in this region besides Monte Urano or Monte Motola/San Benedetto in Perillis if the intermediate road from Popoli is repaired. Fonte Ciarlotto is next to a tunnel known as Olmo di Bobbi, a rather well known climb in the region. They'll be also going through Celano which is overlooking a vast plain/former lake Lago Fucino. I believe the best way would be to have Monte Motola and then Rocca di Mezzo via Sp11 as both those climbs are harder than Fonte Ciarlotto and Ovindoli. You could have better options from l'Aquilla with any of the Gran Sasso climbs and Rocca di Cambio but i guess the stage would be too long.
Foligno - it seems Foligno likes to lobby RCS. Maybe becasue it's the least memorable city next to the likes of Perugia, Assisi, Todi and Spoleto. I remember the finish to be rather twisty and frantic. If you want a transitional but on paper way more interesting stage then you can draw it through Terminillo, Forca Capistrello and Valico di Pettino (12km @ 7,2%) or a lil bit easier Passo Spina next to it.
Montalcino - maybe people are overrating the impact of sterrato. Strade Bianche has the advantage of being a one-day race so everybody's going full gas.The 2010 stage (which wasn't hard at all on paper) did a lot of damage cause back then i feel not many GC people in the peloton had that much experience with dirt. Right not it looks like it's required for a GC guy to know how to ride on different surfaces (...and also be an outright sprinter). I still believe it to be a reduced (15-30 man group) bunch sprint. However, this could be a good chance to try and drop S. Yates, especially with the lack of TT.
Bagno di Romagna - it's a harder variant of the 2017 stage that went via Monte Fumaiolo. I think it may be my favourite design in the entire race, both race-wise and estethically. I think in the future this very region may experience a finish on Eremo Camaldoli after either Consuma or Calla. Consuma itself is a classic climb in Appennino Tosco-Romagnolo.
Zoncolan - in 2011 poeple were blinded by Crostis. I think the organizers lost a chance to have the very narrow Priola side that's as hard as the Ovaro side. Then after reaching the altiport/ski resort descend down to Sutrio on a much wider and better road and have the regular runup on Valcalda before the regular Zoncolan finish. Btw, on the switchbacks of Monte Rest Steve Roche left Visentini in that famous Giro 87 stage where Visentini bonked.
fedaia - great climb, possibly the hardest in the sella group but definityle NOT the most picturesque. it doesn't even hold a candle to Passo Sella, Gardena or the top of Valparola. the Sottoguda gorge is very good but the whole Asturias is littered with such and Vuelta passes such roads almost every year.
Sega di Ala - personally i'm still shocked it's not an Unipuerto stage. There's a secondary road just west of fittanze that has a much harder final section. it's most likely one of the hardest climbs in whole Italy, however the descent would need repaving. You could had a Verona finish that way easily and it would be bonkers if the very last (21st) stage would do that with a Verona grande finale.
Madesimo - while it also had spluga and furka i believe it is the famous stage that Adorni soloed, but becasue Adorni's name doesn't resonate the same as Coppi it had been relatively forgotten. I think Adorni attacked on San Bernardino but i would need to refresh my memory (of what i've read, i'm not that old). A rather well known design idea is to have Spluga south (harder than San Bernardino) and then descent San Bernardino to a finish in Bellinzona. However myself i may prefer to link it up with Albula (and even Fluela for a Davos finish) for a La Punt/Sankt Moritz finish.
Windy stages - i'm not Italian but i believe you never have any significant wind on the Adriatic, at least in May. I know though that there are strong foehns on the Dalmatian (Croatian) side. I think i've seen some slightly more regular weather scenarios of north-western winds in the Foggia plains and maybe slight eastern sea breezes in the east middle of the Po valley (Comacchio/Adria).