The per-row processing architecture of Bulk Execution means that performance is poor when processing anything more than a few thousand records with a few validation rules. On my current project, running Bulk Execution on 5000 records with 10 validation rules takes >6 minutes. The page contains 25000 records and so bulk execution is likely to take >30 minutes. This makes it unusable for business users and so bulk execution has currently been disabled.
Where Validation Rules are based on Views, would it be possible for these to be processed in batch mode, writing the PK and error message to a working table that is then used to populate the Bulk Execution results window?
In the example above, running the 10 validation rules for all 25000 records in SSMS took 2 seconds to return a total of 28,631 rows.