you are saying :"My recommendation to junior developers is pretty simple. Every table gets both a primary key and a clustered index. It may not be a "best" practice, but a damn good starting point is to just add a identity column called rowid and make it the primary key and the clustered key. As your skills increase you can start to look at more advanced alternatives. "
It's a good thing I think also having a primary key . But a clustered index on a table which have 10 million lines is not a good one. Especially in production environnement. if this table have a lot of insert and delete statements, the cost will be very very high (as SQL have to organize physically the lines).
That's my opinion. Whatever, Your article is interesting in that way that (I hope) It'll help newbies to take care about those important things. An other subject that would be interesting: Statistics.