Is this an issue?

I think it depends on how you view the idea of the last days. Was it a one time event when the world came to an end, or is it connected to the idea of the "Day of the Lord" (day of judgment / deliverance) that was very prominent in the message of the Old Testament prophets? I tend to look at the eschatological narratives as not referring to a final end of the world Tim Lehaye type of prophecy. I tend to look at it as another Day of the Lord when God pours out his wrath on the wicked and brings deliverance to the people of God who are being persecuted. Given the context of the times, I think that seems to make more sense. In that context, I think it is fair to say that although the prophets spoke prophecies in the past, he has chosen to speak to the saints of that time through his Son (Christ), and indeed, we find in the Olivet Discourse that he did speak through Christ in the form of prophecy. This, however, does not mean that prophecy, has necessarily ceased. Indeed, Christ spoke to them through prophecy. He prophecied many things which came true (aka...the destruction of the temple, false teachers, etc...). Instead, it is Christ who is speaking to them, even in prophecy himself.

Joseph Botwinick

 

Rev 1:1 The Revelation of Jesus Christ, which God gave unto him, to shew unto his servants things which must shortly come to pass; and he sent and signified it by his angel unto his servant John:

I don't see any problem. The revelation is sent by to John from Jesus by His angel. But the verse in Hebrews is not saying that God will not use prophets anymore. There will still be the two witnesses sent, and the book of Joel seems to indicate that there will be a revival of such things in the tribulation.

Joel 2:28 And it shall come to pass afterward, that I will pour out my spirit upon all flesh; and your sons and your daughters shall prophesy, your old men shall dream dreams, your young men shall see visions: