I dunno if this was mentioned (didn't see it when reading through the comments) but it's confirmed that his tomes DO regenerate overtime.
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But as it turns out, Super Smash Bros. for Wii U and 3DS director Masahiro Sakurai did actually mention that Robin's limited-use moves would regnerate over time, in the same issue of Famitsu; it was mentioned in a column he wrote for the magazine, separate from the 4-page spread.
Sakurai wrote in his Famitsu column, as translated by NeoGAF user Masked Men:
"I also implemented the system used in FE:A, in which tomes break after overuse. Likewise, I included a similar system for the Levin Sword, which breaks after a certain number of uses. However, both the tomes and the Levin Sword will quickly regenerate after a set period of time."
Sakurai also explains the rationale behind his decision in picking Robin and Lucina from Fire Emblem:Awakening to introduce into the new Smash Bros. instead of Chrom (who only appears during Robin's Final Smash attack).
"I played all the way through FE:A and really wanted to include a character from that rich cast in Smash Bros. Naturally, I considered adding Chrom to the roster, but the decision wasn't easy by any means.
"At the end of the day, Chrom would just end up being another plain-old sword-wielder like Marth and Ike. Compared with other characters, he lacks any unique characteristics.
"Conversely, when the idea of including Robin came to mind, conceiving the character was so easy that I immediately saw how it would work. From standards to specials, grabs to throws, all aspects of his moveset just fell into place. Not only did he possess characteristics unlike other fighters, but he also captured the essence of the Fire Emblem series. It was perfect!
"In the end, if a game isn't fun, then there's no point. Of course, it would be really easy to make a game by churning out a ton of similar characters, but that's not how I produce games."