More blocktime estimates have been posted at: https://ethresear.ch/t/blocks-per-week-as-an-indicator-of-the-difficulty-bomb/12120/22 (see last post/graph)

Jun 15 estimated block times: ~15 secs
July 15 estimated block times: ~18 secs
Aug 15 estimated block times: ~21 secs

Vitalik in a previous core dev call said they can tolerate 20-25 sec block times as they've done in the past.

So given the schedule for the upcoming Ropsten testnet merge on Jun 8, plus two weeks running on Ropsten, then a further two testnet merges running for two weeks each, followed by a couple of weeks to schedule mainnet merge, brings it to around mid-Aug.

If their estimates of 21 secs in mid-Aug is correct then they might not delay the bomb anymore (barring any issues during the upcoming testnet merges).