Is there an overview of alternative approaches to voluntary and ideal review process?
You can refer to the following article: "Why do peer reviewers decline to review? A survey" to begin with.

The following extract from the results abstract is quite interesting:


  Most respondents agreed that financial incentives would not be effective when time constraints are prohibitive (mean 3.59 (SD 1.01)). However, reviewers agreed that non-financial incentives might encourage reviewers to accept requests to review: free subscription to journal content (mean 3.72 (SD 1.04)), annual acknowledgement on the journal’s website (mean 3.64 (SD 0.90)), more feedback about the outcome of the submission (mean 3.62 (SD 0.88)) and quality of the review (mean 3.60 (SD 0.89), and appointment of reviewers to the journal’s editorial board (mean 3.57 (SD 0.99)).


So basically, this study confirms what your colleague mentioned about financial incentives not being the best approach to incentivise reviewers (maybe though for different reasons that you might have expected). 

However, keep in mind that people in academia are not motivated only by money (as in that case they wouldn't be in academia in the first place). There are other means to motivate people that are keen to review papers, such as acknowledgements or free subscription to the journal they review, as the article states.