Kusto is fine, but joins are quite horrendous there. To be frank, I don't really get complains about "SQL is not readable". Most of the time SQL is the most compact, clear and to the purpose way to fetch the data (given the data had been modeled in a manner suitable for queriying).
Luckily, most of the tables for KQL in Azure are flat and not complex and that is partially what makes kusto so compelling.