I'd love an opportunity to test these items - they all seem really unique!
The Ancient Coin seems to be attracting a lot of attention, however (iirc, please correct me if I'm wrong!) I faintly remember hearing it will drop little gold/xp piles (similar to Thresh's Souls) that could be picked up by the support or denied from the enemy team. I'm honestly super psyched to see some depth in these items, and having items that let you play a fun game on the side instead of "Push Wave, Dive? Nah just wait till next wave. Rinse and repeat." It could definitely bring a healthy dynamic down in an otherwise boring lane (provided you aren't all-inning at every chance possible) and promotes scaling a little bit - or at the very least getting to do SOMETHING instead of the same ol' song and dance. I immediately hated the Blast Cones when they came out myself, however I've found more often than not they can save you (or your teammate's) life many times over. It won't stop, say, Rek'Sai from tunneling over and killing you again. But at the end of the day it's SOMETHING for mobility/escape for champions that have none. The Honeyfruits work well in a similar manner, get bullied out of top lane and don't have Teleport up/you didn't bring it? Go snatch a few Honeyfruits and come back into lane like nothing happened at all. Maybe kill the Scuttlecrab to make up for any loss in XP, and to further replenish your resources.
Relic Shield seems to do exactly what it's advertising. A small constant shield (similar to Malphite's) that can be broken, however to replenish it you actively need to kill minions with an ally nearby to make the most out of it. So now the ADC will (hopefully) want the gold to be shared instead of pushing the wave so fast Braum can't get his big beefy hands in there to empower them for the next fight - or the current one going on (if it's able to refresh like that). This could definitely lead to some crazy LCS plays and fights that were turned around with better macro-management of your items and timings.
Spellthief's Edge seems tuned towards support champions that want to poke, and poke again, and poke again and again.........while I do enjoy free movement speed, I'm not sure how I feel about the Spellthief's Procs itself granting the movement speed. Zyra will heavily abuse this if her plants are still allowed to proc it, being able to run in and guarantee abilities (and more plants) hit seems difficult to work around. Someone like Morgana can pick this up, pick up Tormented Soil (W) level 1 and guarantee her Spellthief's gets all procs off, as well as TLD for that extra "oomph." The speed will likely be wasted in that situation, as the enemy knows you have nothing else and will trade hard with you if they have their abilities left. However...if it still procs off of Auto-Attacks, I could imagine someone like Morgana or Thresh pick it up, start Q, smack the Support once or twice with Autos, and sprint directly in front of the ADC, almost guaranteeing their CC will land. The dynamics of Bot Lane are always interesting to see, as they've had such a diverse set of champion pools over the years, but usually only a select handful that are deemed "professional play" that rotates from patch to patch.
Either way, I'm super excited to see the changes coming forward, as they will definitely impact the game and meta in a large way, while hopefully bringing in champions that were left untouched for being "boring, binary" or otherwise.