There is so much to say about this, not least the lack of evidence for Jesus. But regarding the spear - why a spear? Surely it would have been a pilum? The transposition, as always, is medieval. During the Second Siege of Antioch in 1098, the desperate crusaders were told by a priest named Peter Bartholomew that the 'Holy Lance' would be found. They found such a weapon, and were inspired to continue. Lance? A spear was said to be among relics held in Constantinople. It doesn't take a leap of imagination to see that this is another example of medieval hypocrisy regarding Christianity.
However, one should be wary of accepting the gospels as history. They were after religious stories written by people other than the saints normally attributed. The four gospels we have as canon today first become forwarded around 160 (not the Council of Nicaea in 325 as normally stated) but please realise that there may have been as many as fifty of them, all diverse, and thus unreliable as accounts.
Incidentially the description you made of Jesus receiving a thrust into the heart isn't something I've heard before and would appear to be a hyped up version of the tale, since a bored legionary asked to confirm a crucified victim had died isn't likely to be so symbolically accurate. he would want a reaction, not a drama.