I know it's one month old, but I thought it was still interesting to mention that now Let's encrypt supports Wildcard certificates : [community.letsencrypt.org...]
LifeinAsia
7:25 pm on Apr 18, 2018 (gmt 0)
Previous discussion here [webmasterworld.com]. Sounds like it might not be quite ready for prime time, but don't know if they've fixed the issue since then.
