I hear you. It just sparked a pet peeve of mine as an interviewer and employee. ;)
I suppose it's easy pointing out flaws without offering solutions.
I think one possible solution would be a system where potential new hires were given real world problems under real world working conditions. Today, people often study for months to "pass" the interview tests. Generally taking up many hours of multiple interviewers time.
Instead, if a potential candidate were given a sufficiently unique and difficult problem and a time window to complete it representative of the desired work output it would provide a much better idea of what kind of employee they would be.
- Did they complete the job earlier than the given time, but turned in sloppy or a less than ideal solution?
- Did they eat up the entire allotted time, but turn in truly stellar work?
- Best of all, turned in early, unique solution with good, commented, test driven code and asking for another problem?
And really who cares if they had to review their algorithms or operating systems book to do it? That's why we keep them on our shelf.
I'd say for sufficiently hard, and original, problems I spend 80% of my time with my nose in a book or reading papers and 20% engineering a solution....unless I'm doing it day in and day out.
After that, it's mostly about personality and team fit. Bring them in to do some white booarding (full access to resources) and work with the team, make sure they aren't smoke and mirrors. Then make a call.
edit
For example, take your ops guy. Best interview I've ever seen for ops is to throw them in a broken sandbox environment, give them root & tell them to fix it, and walk away.