SQL Server 2012 :: Multiple Queries In Same Stored Procedure

Our developers have gotten this idea lately that instead of having many small stored procedures that do one thing and have small parameter lists that SQL can optimize query plans for, its better to put like 8-10 different queries in the same stored procedure.

They tend to look like this:

create procedure UberProc (@QueryId varchar(50))
as

if @QueryId = 'First Horrible Idea'
begin
select stuff from something
end
if @queryid = 'Second really bad idea'
begin
select otherstuff from somethingelse
end

I see the following problems with this practice:

1) SQL can't cache the query plan appropriately
2) They are harder to debug
3) They use these same sorts of things for not just gets, but also updates, with lots of optional NULLable parameters that are not properly handled to avoid parameter sniffing.